Infrared Emitters and Detectors Data Book

1994

TELEFUNKEN Semiconductors Table of Contents TELEFUNKEN Semiconductors

General Information 1. Selector guide 11 1.1 Alpha-numeric index 11 1.2 IR emitters 12 1.3 Detectors 14 1.4 Photomodules 17 1.5 IrDA-infrared data transmission 18 2. Explanation of technical data 19 2.1 Type designation code for semiconductor devices according to Pro Electron 19 2.2 TEMIC Type designation systems 20 3. Data sheet illustration 21 3.1 Symbols and terminology 21 3.2 Data sheet construction 29 3.2.1 Device description 29 3.2.2 Absolute maximum ratings 29 3.2.3 Thermal data – thermal resistances 29 3.2.4 Basic characteristics 30 3.2.5 Family of curves 30 3.2.6 Dimensions (Mechanical data) 30 4. Physics and technology 31 4.1 Emitters 31 4.1.1 Materials 31 4.1.2 IRED chips and characteristics 31 4.2 UV, visible, and near IR silicon photodetectors 34 4.2.1 Silicon photodiodes 34 4.2.1.1 The physics of silicon detector diodes 34 4.2.2 Properties of silicon photodiodes 35 4.2.2.1 I-V Characteristics of illuminated pn junction 35 4.2.2.2 Spectral responsivity 36 4.2.2.2.1 Efficiency of Si photodiodes 36 4.2.2.2.2 Temperature dependence of spectral responsivity 37 4.2.2.2.3 Uniformity of spectral responsivity 37 4.2.2.2.4 Stability of spectral responsivity 37 4.2.2.2.5 Angular dependence of responsivity 37 4.2.2.3 Dynamic properties of Si photodiodes 38 4.2.3 Characteristics of other silicon photodetectors 38 4.2.3.1 Avalanche photodiodes 38 4.2.3.2 Phototransistors 38

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4.2.4 Applications 39 4.2.4.1 Equivalent circuit 39 4.2.4.2 Searching for the right detector diode type 39 4.2.4.3 Operating modes and circuits 41 4.2.4.4 Frequency response 41 4.2.4.5 Which type for which application? 43 4.2.5 Phototransistors 43 4.2.5.1 Circuits 43 5. Measurement techniques 44 5.1 Introduction 44 5.2 Dark and light measurements 44 5.2.1 Emitter devices 44 5.2.1.1 IR diodes (GaAs) 44 5.2.1.2 Light emitting diodes 45 5.2.2 Detector devices 46 5.2.2.1 Photovoltaic cells, photodiodes 46 5.2.2.2 Phototransistors, photodarlington transistors 47 5.2.3 Coupling devices 48 5.3 Switching characteristics 49 5.3.1 Definition 49 5.3.2 Notes concerning the test set-up 49 5.3.3 Switching characteristic improvements on phototransistors and darlington phototransistors 49 6. Component construction 50 7. Tape and reel standards 51 7.1. Packing 51 7.1.1 Number of components 51 7.1.2. Missing components 51 7.2 Order designation 51 7.2.1 Tape dimensions for ∅ 3 mm standard packages 52 7.2.2 Tape dimensions for ∅ 5 mm standard packages 53 7.2.3 Reel package, dimensions in mm 54 7.2.4 Fan-fold packing 56 7.3 Taping of SMT-devices 57 7.3.1 Number of components 58 7.3.2 Missing devices 59 7.3.3 Top tape removal force 59 7.3.4 Ordering designation 59

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8. Assembly instructions 60 8.1 General 60 8.2 Soldering instructions 60 8.3 Heat removal 62 8.4 Cleaning 63 8.5 Warning 63 9. Quality information 64 9.1 Quality management 64 9.1.1 TEMIC continuous improvement activities 64 9.1.2 TEMIC tools for continuous improvement 64 9.1.3 TEMIC quality policy 64 9.2 General quality flow chart diagram 65 9.2.2 Production flow chart diagram 66 9.3 Qualification and monitoring 67 9.3.1 Qualification procedure 67 9.3.2 Quality indicators 67 9.4 Failure rates: FIT 67 9.5 Degradation of IREDs 68 9.6 Safety 68 9.6.1 Reliability and safety 68 9.6.2 Toxicity 68 9.6.3 Safety aspects of IR radiation 68

Technical Data Infrared Emitters 69 Photodetectors 231 Photomodules for PCM Remote Control Systems 479 Infrared Data Transmission 493 Addresses 519

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1. Selector guide 1.1 Alpha-numeric index

B BPW 97 369 TEMT 4700 461 BPX 38 379 TEST 2500 467 BP 104 233 BPX 43 385 TEST 2600 473 BPV 10 245 BPX 99 R 391 TFDS 3000 513 BPV 10 F 237 TFMS 5..0 481 BPV 10 NF 241, 503 BPV 11 255 C TFMT 5..0 487 TSCA 6000 89 BPV 11 F 249 CQX 19 71 BPV 20 F 261 TSHA 440. 95 CQX 48 75 BPV 20 NFL 265 TSHA 520. 101 CQY 36 N 81 BPV 21 F 269 TSHA 550. 107, 495 CQY 37 N 85 BPV 22 F 273 TSHA 620. 113 BPV 22 NF 277, 505 TSHA 650. 119 BPV 23 F 281 I TSHF 5400 125, 499 BPV 23 NF 285, 507 IrDA Evaluation Kit 509 TSIP 440. 129 BPV 23 NFL 289 TSIP 520. 135 BPW 13 293 S TSIP 760. 141 BPW 14 N 297 TSMS 3700 147, 151 BPW 16 N 301 S 153 P 395 TSSA 2500 157 BPW 17 N 307 S 186 P 399 TSSA 4500 163, 497 BPW 20 R 313 S 239 P 403 TSSF 4500 167, 501 BPW 21 R 317 S 254 P N 407 TSSP 4400 171 BPW 24 R 321 S 268 P 411 TSSS 2600 177 BPW 34 325 S 289 P 417 TSTA 7100 183 BPW 41 N 329 S 350 P 421 TSTA 7300 187 BPW 43 333 S 351 P 427 TSTA 7500 191 BPW 46 337 BPW 76 375 TSTS 710. 195 BPW 77 N 341 T TSTS 730. 199 BPW 78 345 TEFT 4300 433 TSTS 750. 203 BPW 82 351 TEMD 2100 439 TSUS 4300 207 BPW 83 355 TEMT 2100 443 TSUS 4400 213 BPW 85 359 TEMT 2200 449 TSUS 520. 219 BPW 96 365 TEMT 370. 455 TSUS 540. 225

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1.2 IR emitters Infrared emitting diodes Characteristics PackagePackage TypeType +/– ϕ tr , tf / ns Ie / mW/sr @ IF / mA VF / V @ IF / mA IR emitter GaAs (950 nm) in plastic package

CQY 36 N 40_ 400 1.5(>0.7) 50 1.2(<1.6) 50

CQY 37 N 12_ 400 4.5(>2.2) 50 1.2(<1.6) 50

TSUS 4300 20_ 400 18(>7) 100 1.3(<1.7) 100

TSUS 4400 16_ 400 15(>7) 100 1.3(<1.7) 100

CQX 48 A 1–3 25_ 400 50 11.2(<1.7) 2(<1 7) 50 CQX 48 B 4(>2.0) TSSS 2600 25_ 400 1.5(>0.6) 50 1.2(<1.6) 50

TSUS 5200 20(>10) TSUS 5201 15_ 400 25(>15) 100 1.3(<1.7)() 100 TSUS 5202 30(>20) TSUS 5400 14(>7) TSUS 5401 22_ 400 17(>10) 100 1.3(<1.7) 100 TSUS 5402 20(>15) IR emitter GaAlAs (875 nm) in plastic package

TSHA 4400 20(>12) 20_ 300 100 1.5(<1.8)1 5(<1 8) 100 TSHA 4401 30(>16) TSSA 2500 25_ 300 10(>3.5) 100 1.5(<1.8) 100

TSSA 4500 20_ 300 23 100 1.5(<1.8) 100

TSHA 5200 40(>25) TSHA 5201 50(>30) 12_ 300 100 11.5(<1.8) 5(<1 8) 100 TSHA 5202 60(>36) TSHA 5203 65(>50) TSHA 5500 20(>12) TSHA 5501 25(>16) 24_ 300 100 11.5(<1.8) 5(<1 8) 100 TSHA 5502 30(>20) TSHA 5503 35(>24) TSHA 6200 40(>25) TSHA 6201 50(>30) 12_ 300 100 1.5(<1.8)1 5(<1 8) 100 TSHA 6202 60(>36) TSHA 6203 65(>50) TSHA 6500 20(>12) TSHA 6501 25(>16) 24_ 300 100 11.5(<1.8) 5(<1 8) 100 TSHA 6502 30(>20) TSHA 6503 35(>24) TSCA 6000 4° 300 120(>70) 100 1.5(<1.8) 100

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Characteristics PackagePackage TypeType +/– ϕ tr , tf / ns Ie / mW/sr @ IF / mA VF / V @ IF / mA IR emitter GaAlAs/GaAs (950 nm) in plastic package

TSIP 4400 25(>12) 20_ 500 100 11.3(<1.8) 3(<1 8) 100 TSIP 4401 30(>16) TSSP 4400 20_ 500 23(>10) 100 1.3(<1.8) 100

TSIP 5200 40(>20) 17_ 500 100 11.3(<1.8) 3(<1 8) 100 TSIP 5201 50(>30) TSIP 7600 15(>8) 30_ 500 100 11.3(<1.8) 3(<1 8) 100 TSIP 7601 20(>12) IR emitter GaAlAs/GaAs (950 nm) in SMD package

TSML 3700 60° 500 7 100 1.3 100

IR emitter GaAs (950 nm) in SMD package

TSMS 3700 60_ 400 4 100 1.3(<1.7) 100

TSMS 2100 60_ 400 1 50 1.2(<1.7) 50

IR emitter GaAs (950 nm) in hermetically sealed package

TSTS 7100 25(>10) TSTS 7101 12–25 5_ 400 100 11.4(<1.7) 4(<1 7) 100 TSTS 7102 20–40 TSTS 7103 32–64 TSTS 7300 15(>4.0) TSTS 7301 6.3–12.5 12_ 400 100 1.4(<1.7)1 4(<1 7) 100 TSTS 7302 10–20 TSTS 7303 16–32 TSTS 7500 3(>1.2) TSTS 7501 1.6–3.2 40_ 400 100 11.4(<1.7) 4(<1 7) 100 TSTS 7502 2.5–5.0 TSTS 7503 4.0–8.0 IR emitter GaAlAs (875 nm) in hermetically sealed package

TSTA 7100 5_ 30(>20)

TSTA 7300 12_ 500 15(>10) 100 1.4(<1.8) 100

TSTA 7500 40_ 6(>3.2)

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Characteristics PackagePackage TypeType +/– ϕ tr , tf / ns Ie / mW/sr @ IF / mA VF / V @ IF / mA IR emitter GaAs (950 nm) with metal socket and plastic lens

CQX 19 20_ 700 40 250 1.2 250 1.3 Detectors Phototransistors Photo Characteristics SensitiveS iti +/–/ ϕ 2 m W Packageg Typeyp Area Ica / mA @ Ee / mW / cm tr / s @ RL / k 2 mm (VCE = 5 V, l = 950 nm) (IC = 5 mA, l = 950 nm) Phototransistors in clear plastic package

BPW 16 N 40_ 0.14(>0.07) 0.360.36 1 3.73.7 0.10.1 BPW 17 N 12.5_ 1.0(>0.5)

BPW 85 A 0.8–2.5 BPW 85 B 0.18 25_ 1.5–4.0 1 1.5 0.1 BPW 85 C 3.0–8.0 BPW 96 A 1.5–4.5 BPW 96 B 0.18 20_ 2.5–7.5 1 1.5 0.1 BPW 96 C 4.5–15 BPV 11 15_ 10(>3) 0.360.36 1 3.83.8 0.10.1 S 351 P 20_ >4

TEPT 4700 0.36 60° 0.7–2.1 1 3.8 0.1

TEYT 5500 0.18 0.6(>0.4) 1 1.5 0.1

SMD Phototransistors in clear plastic package

TEMT 2100 0.45(>0.3) 0180.18 70_ 1 151.5 010.1 TEMT 2200* 0.45(>0.3) TEMT 3700 0.5(>0.2) 0070.07 70_ 1 5 1 TEMT 4700* 0.5(>0.2) * with base connected

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Photo Characteristics SSensitive iti +/–/ ϕ 2 m W Packageg Typeyp Area Ica / mA @ Ee / mW / cm tr / s @ RL / k 2 mm (VCE = 5 V, l = 950 nm) (IC = 5 mA, l = 950 nm) Phototransistors in plastic package with filter matched for GaAs IREDs (950 nm)

S 350 P 0.36 40_ 1(>0.2) 1 3.8 0.1

BPW 78 A 25_ 1.0–3.0 0360.36 1 383.8 010.1 BPW 78 B 25_ 4(>2.0)

TEFT 4300 0.18 30_ 3.2(>0.8) 1 1.5 0.1

TEST 2500* 0.36 35_ 6(>3.0) 1 3.8 0.1

TEST 2600 0.36 30_/60_ 2.5(>1.0) 1 3.8 0.1

BPV 11 F 0.36 15_ 9(>3.0) 1 3.8 0.1 * filter matched for GaAlAs IREDs Photodarlington in plastic package with filter matched for GaAs IREDs (950 nm)

S 289 P 0.21 30_ 15(>4.0) 0.3 80 0.1

Phototransistors in hermetically sealed package

BPW 76 A 0.4–0.6 0360.36 40_ 1 383.8 010.1 BPW 76 B 1.2(>0.6) BPX 38 >0.5 BPX 38-4 0.5–1.0 15 0.76076 40_ 0.505 1 BPX 38-5 0.8–1.6 20 BPX 38-6 >1.25 25 BPW 77 NA 7.5–15 0360.36 383.8 BPW 77 NB 10_ 20(>10.0) 1 0.1 S 254 PN 0.18 >3.0 1.5 BPX 43 >2.0 BPX 43-4 2.0–4.0 15 0.76076 15_ 0.505 1 BPX 43-5 3.2–6.3 20 BPX 43-6 >5.0 25 Photodarlington transistor in hermetically sealed package

BPX 99 R-2 10(>4.0) 0210.21 1212.5 5_ 030.3 80 010.1 BPX 99 R-3 20(>10.0)

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PIN photodiodes

Photo Characteristics Sensitive +/–/ ϕ m l / W Packageg Typeyp Area Ira / A @ nm ton/ns @ RL / 2 2) mm (Ee = 1 mW/ cm (l = 820 nm) (VR = 10 V) PIN photodiodes in clear plastic package

BPW 34 7.5 65_ 50(>40) 950 100 1000

BPW 46 7.5 65_ 50(>40) 950 100 1000

BPW 43 0.25 25_ 8(>4) 950 4 1) 50

BPV 10 0.78 17,5_ 65(>38) 950 2.5 2) 50

S 268 P 3x7.5 65_ 50(>40) 950 100 1000

TEMD 2100 0.25 75° 2.3 950 2.5 1)2) 50

PIN photodiodes in plastic package with filter matched for GaAlAs IREDs (875 nm)

BPW 82 * 7.5 65_ 48(>41) 870 100 1000

BPW 83 * 7.5 65_ 50(>41) 870 100 1000

BPV 20 NFL 7.5 65_ 60(>40) 870 100 1000

BPV 22 NF 7.5 60_ 85(>55) 870 100 1000 BPV 23 NF* 5.7 60_ 65(>45) 870 70 1000 BPV 23 NFL 5.7 60_ 65(>45) 870 100 1000 PIN photodiodes in plastic package with filter matched for GaAs IREDs (950 nm)

BP 104 7.5 65_ 45(>40) 950 100 1000

BPW 41 N * 7.5 65_ 45(>41) 950 100 1000

S 186 P * 7.5 65_ 45(>41) 950 100 1000

BPV 20 F * 7.5 65_ 60(>40) 950 100 1000 BPV 21 F * 5.7 65_ 38(>27) 950 70 1000 BPV 22 F * 7.5 60_ 80(>55) 950 100 1000 BPV 23 F * 5.7 60_ 63(>45) 950 70 1000

BPV 10 F 0.78 17.5_ 60(>30) 950 2.5 1)2) 50

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Photo Characteristics Sensitive +/–/ ϕ m l / W Packageg Typeyp Area Ira / A @ nm ton/ns @ RL / 2 2) mm (Ee = 1 mW/ cm (l = 820 nm) (VR = 10 V) PIN photodiodes in hermetically sealed package for standard applications

S 153 P 7.5 50_ 50(>40) 950 100 1000

BPW 24 R 0.78 12_ 65(>45) 950 7 1)3) 50

Quadrant photodetector

S 239 P 4 2.25 50° 15 (u10 ) 870 150 1000

PIN photodiode in hermetically sealed package for glass fiber applications (Anode and cathode insulated from case)

BPW 97 0.25 55° 1.3 (u1 ) 870 0.6 50

Photodiodes for light measurement applications Photo Characteristics Sensitive +/–/ ϕ m m W Packageg Typeyp Area Ik / A V0 / mV ton / s @ RL / k 2 mm (EA = 1 klx) (Iph = 100 mA)

BPW 20 R 7.5 50_ 61(>20) 500 3.5 1) 1 BPW 21 R 7.5 50_ 9(>4.5) 450 3.5 1) 1 (with V(l)filter) 1) 2) 3) tr, tf VR = 50 V VR = 20 V * long lead packages optional: suffix ”L”, e.g. BPV 23 NFL 1.4 Photomodules Photomodules for pulse code remote control systems * standard applications

Characteristics Package Type f l V E min O S e Features (kHz) (nm) (V) mW/m2

TFMS 5300 30 Photo detector and pppreamplifier in one pgpackage TFMS 5330 33 RReliableeliable functionfunction even inin disturbeddisturbed ambientambient TFMS 5360 36 950 5 0350.35 IInternal l protection i against i uncontrolled ll d output TFMS 5380 38 pulses TFMS 5400 40 InternalI l shielding, hi ldi daylight d li h filter fil epoxy package k TFMS 5560 56 TFMT 5300 30 Highgy sensitivity and maximum interference safety y againstit optical til and dltilditb electrical disturbances TFMT 5330 33 TFMT 5360 36 Outputpg signal compatible p to micro computers p 950 5 0.35035 TFMT 5380 38 Maximum dutyduty cyclecycle of 40 %, minimum burst TFMT 5400 40 length 400 ms TFMT 5560 56

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1.5 IrDA-infrared data transmission Emitters

Characteristics PkPackage TType +/– ϕ tr , tf / ns Ie / mW/sr @ IF / mA VF / V @ IF / mA

TSHA 5500 20(>12) TSHA 5501 25(>16) 24_ 300 100 TSHA 5502 30(>20) TSHA 5503 35(>24) 1.5(<1.8) 100 TSSA 4500 20_ 300 23 100 1.5(<1.8) 100

TSHF 5400 24° 30 30 100 1.35(<1.6) 100

TSSF 4500 22° 30 20 100 1.35(<1.6) 100 Detectors Photo Characteristics Sensitive +/–/ ϕ m l / W Packageg Typeyp Area Ira / A @ nm ton/ns @ RL / 2 2) mm (Ee = 1 mW/ cm (l = 820 nm) (VR = 10 V)

BPV 10 NF 0.78 20° 55 870 2.5 50

BPV 22 NF 7.5 60° 85(>55) 870 100 1000 BPV 23 NF 5.7 60° 65(>45) 870 70 1000 Transceivers Data Rate / kBit/s PPackageackage TTypeype +/–+/ ϕ VV/VS / V dd/mmin / m ttt/nsr , tf / ns Min Max

TFDS 3000*) 20_ 5 1 < 200 2.4 115.2

*) Production series of Integrated Transceiver starts in March ’95. IrDA Evaluation Kits (discrete assembly on PCB with same function) are available.

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2. Explanation of technical data 2.1 Type designation code for semiconductor devices according to Pro Electron

The type number of semiconductor devices consists of: Two letters followed by a serial number

For example: B P W20

Material Function Serial number The first letter gives information frequency U TRANSISTOR: Power, switching about the material used for the active E DIODE: Tunnel part of the devices. X DIODE: Multiplier, e.g. varactor, F TRANSISTOR: Low power, high step recovery A GERMANIUM frequency (Materials with a bandgap Y DIODE: Rectifying, booster 1) 0.6–1.0 eV) G DIODE: Oscillator, Z DIODE: Voltage reference or Miscellaneous B SILICON voltage regulator. (Materials with a bandgap 1.0–1.3 H DIODE: Magnetic sensitive Transient suppressor diode eV) 1) K HALL EFFECT DEVICE: in an The serial number consists of: C GALLIUM-ARSENIDE open magnetic circuit D (Materials with a bandgap > 1.3 Three figures, running from 100 to L TRANSISTOR: Power, high eV) 1) 999, for devices primarily frequency intended for consumer equipment. R COMPOUND MATERIALS M HALL EFFECT DEVICE: in a (For instance Cadmium-Sulphide) D One letter (Z, Y, X, etc.) and two closed magnetic circuit figures running from 10 to 99, for The second letter indicates the circuit N PHOTO COUPLER devices primarily intended for function: professional equipment. P DIODE: Radiation sensitive A DIODE: Detection, switching, A version letter can be used to indicate mixer Q DIODE: Radiation generating a deviation of a single characteristic, B DIODE: Variable capacitance R THYRISTOR: Low power either electrically or mechanically. The letter never has a fixed meaning, C TRANSISTOR: Low power, S TRANSISTOR: Low power, the only exception being the letter R, audio frequency switching indicating reversed voltage, i.e. D TRANSISTOR: Power, audio T THYRISTOR: Power collector to case.

1) The materials mentioned are examples

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2.2 TEMIC Type designation systems

TE F F F F FFFF

TELEFUNKEN Semiconductors Series P= Plastic Internal F= Plastic Filter Classification S= Side View M=Miniature Y= Fiber Optic Package varieties

Detector Technology T = Phototransistor S = Photo Schmitt-Trigger P = PIN photodiode D Phtdid

TS F F FFFFFFF

TELEFUNKEN Internal Semiconductors Classification Series Package design Main U= Universal, 950 nm ∅ U 2 = 1.8 mm Type H= High eff., 875 nm ∅ M= Micropack, SMD H 3 = 3 mm I with stand offs T = Metal ∅ I = High int., 950 nm F 4 = 3 mm without stand offs F = Fast, 830 nm ∅ S = Side view 5 = 5 mm with stand offs 6,7 = 5 mm∅ without stand offs T 7 = TO 18 8 = TO 39 Selection IR Emitter S = GaAs: Si Type

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3. Data sheet illustration 3.1 Symbols and Candela on an element of the surface SI unit of luminous intensity Iv containing the point, by the area of terminology that element CD Diode capacitance dFe A Ee = Anode, anode terminal Total capacitance effective between dA the diode terminals due to case, E ”ON” A junction and parasitic capacitances. e Radiant sensitive area Irradiance for threshold ”ON” 2 2 That area which is radiant sensitive Cj Unit: W/m or mW/cm Junction capacitance for a specified range. E Capacitance due to a pn junction of a v Illuminance (at a point of a surface) a diode. Quotient of the luminous flux incident Distance between the emitter (source) It decreases with increasing reverse on an element of the surface and the detector. voltage. containing the point, by the area of AQL E that element. Emitter, emitter terminal Acceptable Quality Level dFv (phototransistor) Ev = B dA E Base, base terminal A Unit: lx (Lux) = lm/m2 Illumination at standard illuminant A C According to DIN 5033 and IEC f Capacitance 306–1, illumination emitted from a Frequency tungsten filament lamp with a color Unit: Hz (Hertz) C temperature Tf = 2855.6 K which is Cathode, cathode terminal equivalent to standard illuminant A. fc Collector, collector terminal Unit: lx (Lux) or klx. Cut-off frequency – detector devices The frequency at which the incident _C EA amb radiation generates a photocurrent or Centigrade resp. degree Celsius Ambient illumination at standard a photovoltage of the 0.707 times the Unit of the centigrade scale; can also illuminant A value of radiation at f = 1 kHz. be used (beside K) to express EA(TO) temperature changes. fs Switch-on illuminance (standard Symbols: T, DT Switching frequency illuminant A) of a photo threshold T (_C) = T (K) – 273 switch. GB Gain bandwidth product CCEO E A(TU) Gain bandwidth product is defined as Collector-emitter capacitance Switch-off illuminance Capacitance between the collector the product of M times the frequency and the emitter with open base. Ee of measurement, when the diode is Irradiance (at a point of a surface) biased for maximum obtainable gain cd Quotient of the radiant power incident (avalanche photodiode).

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H Radiant intensity Ie of emitters is Ira Hysteresis typically measured with an angle Reverse light current v0.01 sr on mechanical axis or Reverse current under irradiation H = 100 (E – E )/E (%) eON eOFF eON off-axis in the maximum of the (IEC747–5) Ia irradiation pattern. Reverse light current which flows due to a specified irradiation/illumination Light current dF I = e in a photo electric device. General: Current which flows through e dW a device due to Ira = Iro + Iph irradiation/illumination. Unit: W/sr, mW/sr Iro IB IF Reverse dark current Base current Continuous forward current Dark current (IEC747–5) The current flowing through the diode Reverse current flowing through a IBM in the direction of lower resistance. Base peak current photo electric device in the absence of irradiation. I I FAV C Average (mean) forward current I Collector current SB Quiescent current I I FM ca Peak forward current ISD Collector light current Supply current in dark ambient Collector current under irradiation IFSM (IEC747–5) Surge forward current ISH Collector current which flows at a Supply current in bright ambient I specified illumination/irradiation. k I Short circuit current v Luminous intensity (of a source in a ICEO That value of the current which flows given direction) Collector dark current, with open base when a photovoltaic cell or a Quotient of the luminous flux leaving Collector emitter dark current photodiode is short circuited (R % R L i the source propagated in an element (IEC747–5) ) at its terminals. For radiant sensitive devices with of solid angle containing the given open base and without Iph direction by the element of solid illumination/radiation (E = O). Photocurrent (photo electric current) angle. That part of the electric current in a Luminous intensity Ie of emitters is ICM photo electric detector which is typically measured with an angle Repetitive peak collector current produced by the photo electric effect. v0.01 sr on mechanical axis or off-axis in the maximum of the I e Io irradiation pattern. Radiant intensity (of a source in a dc output current given direction) dFv Iv = Quotient of the radiant power leaving IR dW the source propagated in an element Reverse current, leakage current Unit: cd (candela), lm/sr of solid angle containing the given Current which flows when reverse direction, by the element of solid bias is applied to a semiconductor Iv av angle. junction. Luminous intensity, average

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F K a plane perpendicular to the given M = d v Kelvin direction. v dA The SI unit of temperature T (also 2 d Fv Unit: lm/m2 called the Kelvin temperature); can Lv = dW dA cos q also be used for temperature N.A. differences (formerly _K). Unit: cd/m2 Numerical Aperture N.A. = sin a/2 L lx e This therm is used for the Radiance (in a given direction, at a Lux characteristic of sensitivity or point on the surface of a source or a intensity angles of fiber optics and detector, or at a point on the part of a M objectives. beam) The voltage dependent photocurrent Quotient of the radiant flux leaving, gain M is defined as the ratio of NEP at a certain reverse arriving at, or passing through an photocurrent Iph Noise Equivalent Power voltage to the photocurrent at a bias of element of surface at this point and 10 V (avalanche photodiode). P propagated in directions defined by an tot Total power dissipation elementary cone containing the given m direction, by the product of the solid Matching factor Pv angle of the cone and the area of the Emitter arrays: Power dissipation, general orthogonal projection of the element The ratio of the minimum to the Q of surface on a plane perpendicular to e maximum radiant intensity value Radiant energy the given direction. measured on the devices constituting Energy emitted, transferred or 2 d Fe an array. Le = received in the form of radiation. dW dA cos q Detector arrays: The ratio of the minimum to the Qe = s Fe dt Unit: W or mW sr m2 sr cm2 maximum light current of the devices Unit: J (Joule), Ws constituting an array. Q lm v Luminous energy of light Lumen Me Radiant exitance (at a point of a Product of luminous flux and its Luminous flux, F v surface) duration. Quotient of the radiant flux leaving an Lv Qv = s Fv dt Luminance (in a given direction, at a element of the surface containing the Unit: lm s (lumen second) point on the surface of a source or a point, by the area of that element. RD receptor, or at a point on the path of a dFe Me = Dark resistance beam).Quotient of the luminous flux dA leaving, arriving at, or passing R Unit: W/m2 F through an element of surface at this Feedback resistor point and propagated in directions Mv R defined by an elementary cone Luminous emittance (at a point of a H Resistor for programming the containing the given direction, by the surface) hysteresis of a photo threshold switch. product of the solid angle of the cone Quotient of the luminous flux leaving and the area of the orthogonal an element of the surface containing Ri projection of the element of source on the point, by the area of that element. Internal resistance

23 TELEFUNKEN Semiconductors

Ris e.g. the radiation power Fe(l) at a tpi Isolation resistance specified wavelength l is falling on Input pulse duration the radiation sensitive area of a R L detector, which generates a t Load resistance po photocurrent Iph. s(l) is the ratio Output pulse duration RS between the generated photocurrent Serial resistance Iph and the radiation power Fe(l) Tamb falling on the detector. Ambient temperature Rsh If self-heating is significant: I Shunt resistance is defined and s(l) = ph Temperature of the surrounding air F l measured at a voltage of 10 mV e( ) below the device, under conditions of forward or reverse, or peak to peak Unit: A or mA thermal equilibrium. W mW R(TO) If self-heating is insignificant: Air temperature in the surroundings of Resistor for programming the s(l)rel threshold of a photo threshold switch Spectral sensitivity, relative the device. Ratio of the radiant sensitivity at any RthJA considered wavelength s(l) to the Tamb Thermal resistance, junction to Ambient temperature range radiant sensitivity s(lo) at a certain ambient As an absolute maximum rating: wavelength lo taken as a reference. R The maximum permissible ambient thJC s(l) Thermal resistance, junction to case s(l) = temperature range. rel s(lo) S s(lo) TC Sensitivity, absolute Spectral sensitivity at reference Temperature coefficient Ratio of the output value Y of a wavelength lo The ratio of the relative change of an radiant sensitive device to input value electrical quantity to the change in l X of a physical quantity: s( p) temperature (DT) which causes it, l Spectral sensitivity at wavelength p under otherwise constant operating S + Y X sr conditions. Unit: A/lx, A/W Steradian Unit of solid angle W Tcase S(TH) Case temperature Threshold sensitivity T The temperature measured at a s(l) Period (duration) specified point on the case of a Absolute spectral sensitivity, at a T semiconductor device. wavelength l Temperature Unless otherwise stated, this The ratio of the output quantity to the 0 K = –273.16_C temperature is given as the radiant input quantity in the range of Unit: K (Kelvin), _C temperature of the mounting base for wavelengths l to (l + dl): (Centigrade/degree Celsius) devices with metal can. dy(l) s(l) + t td dx(l) Time Delay time

24 TELEFUNKEN Semiconductors

Tf VBEO operating point is within the color temperature Base emitter voltage, open collector saturation region. Temperature of the thermal radiator V(BR) which emits radiation of the same Saturation Regio chromaticity as the radiation Breakdown voltage IC considered. Reverse voltage at which a small increase in voltage results in a sharp Unit: K (Kelvin). rise of reverse current. It is given in technical data sheet for a specified tf given IC Fall time current. V Tj (BR)CEO Junction temperature Collector emitter breakdown voltage, The spatial mean value of open base temperature during operation. In case V(BR)EBO of phototransistors, it is mainly the Emitter base breakdown voltage, 94 8620 V temperature of collector junction open collector CESat because its inherent temperature is maximum. V(BR)ECO Figure. 3.1 Emitter collector breakdown voltage, t off open base Turn-off time VEBO Emitter base voltage, open collector t VCBO on Collector base voltage, open emitter Turn-on time VECO Generally reverse biasing is to apply Emitter collector voltage, open base tp a voltage to any of two terminals of a Pulse duration transistor in such a way that one of the VF Forward voltage t junction operates in reverse direction, r The voltage across the diode Rise time whereas the third terminal (second junction) is specified separately. terminals which results from the flow ts of current in the forward direction. Storage time VCE Collector emitter voltage Vis Tsd Isolation voltage – opto isolator Soldering temperature VCEO Maximum allowable operating Maximum allowable temperature for Collector emitter voltage, open base voltage between input and output. soldering with specified distance (IB = 0) V from case and its duration. O VCEsat Open circuit voltage Tstg Collector emitter saturation voltage Voltage measured between the Storage temperature range Saturation voltage is the dc voltage photovoltaic cell or photodiode The temperature range at which the between collector and emitter for terminals at a specified device may be stored or transported specified (saturation) conditions i.e. radiation/illumination, if the circuit is without any applied voltage. IC and EV (Ee or IB) whereas the open

25 TELEFUNKEN Semiconductors

VOH Vph radiation/illumination. Output voltage high Photovoltage V Voltage generated between the O Output voltage VOL photovoltaic cell or photodiode Output voltage low terminals due to

Vno Angle of half intensity lp Signal to noise ration Wavelength of peak sensitivity or ϕ1/2 emission VR Angle of half transmission distance Reverse voltage l DVo Voltage drop which results from the Wavelength, general Output voltage change (differential flow of a reverse current. The wavelength of an output voltage) VS electromagnetic radiation. Dl Supply voltage l0.5 Spectral half bandwidth The wavelength interval within which V(l) Range of spectral bandwidth (50 %) the spectral sensitivity or spectral Standard luminous efficiency The range of wavelengths within emission falls to half peak value. function for photopic vision which the spectral sensitivity or spectral emission remains within 50 Fe ϕ = a/2 % of the maximum value. Angle of half sensitivity Radiant flux, radiant power lD Power emitted, transferred, or ϕ = a/2 Dominant wavelength received in form of radiation. dQ F = e e dt Unit: W (Watt) A quantity derived from the radiant Km = 683 lm/W: l flux by spectrally V( ) – weighting of Fv = Km*ŕV(l)*Fe(l)*dl Fv the radiation spectrum multiplied by Luminous flux the photometric efficiency constant dQ F = v v dt Unit: lm (lumen) The space enclosed by rays which sphere with radius r and that the cone h emerge from a single point and lead to intersects with the surface of the Quantum Efficiency all the points of a closed curve. If it is sphere, then the size of the surface W assumed that the apex of the cone area (A) of the sphere subtending the formed in this way is the center of a cone is a measure of the solid angle Solid angle, see figure 3.2 A W = r2 There are 4p sr in a complete sphere. W = 2p (1 – cos a/2) = 4p sin2 a/4 A cone with an angle of half sensitivity a/2 forms a solid angle of Unit: sr (Steradian)

26 TELEFUNKEN Semiconductors

W = 4psr

a = 65.5°

W = 1.0sr

a = 2 arc cos ( 1–W / 2p )

a = 20.5°

W = 0.01sr W = 0.1sr

a = 6.5° 94 8584

Figure 3.2

27 TELEFUNKEN Semiconductors

Examples of the application of the symbols according to 41785 and IEC 148 a) Transistor

AC Value

Icav Collector Current ICAV

ICM IC

without Signal with Signal 93 7795 e Figure 3.3 IC dc value, no signal ICAV Average total value ICM;IC Maximum total value ICEFF RMS total value IC;ICEFF RMS varying component ICM;IC Maximum varying component value iC Instantaneous total value iC Instantaneous varying component value

It is valid:

ICM = ICAV + ICM

2 2 ICEFF = pI CAV + I ceff

iC = ICAV + ic

28 TELEFUNKEN Semiconductors VF

VFSM

VFRM VFWM

VRWM VRRM

VRSM

Figure 3.4 VF Forward voltage VR Reverse voltage VFSM Surge forward voltage (non-repetitive) VRSM Surge reverse voltage (non-repetitive) VFRM Repetitive peak forward voltage VRRM Repetitive peak reverse voltage VFWM Crest working forward voltage VRWM Crest working reverse voltage

c) Designation and symbols of optoelectronic devices are given so far as possible, according to DIN 44020 sheet 1 and IEC publication 50(45).

29 TELEFUNKEN Semiconductors

Terms of Radiometry and Photometry

Radiometric Units Photometric Units Unit Symbol Unit Unit Symbol Unit Note Radiant flux, Fe Watt, W Luminous flux Fv Lumen, lm Power Radiant power 2 2 Radiant exitance, Me W/m Luminous Mv lm/m Output power per unit area Emittance emittance (Radiant) intensity Ie W/sr (Luminous) Iv Candela, Output power per unit solid intensity cd, lm/sr angle 2 Radiant sterance, Le W Luminance Lv cd/m Output power per unit solid Radiance sr*m2 (Brightness, angle and emitting area sterance) 2 2 Radiant incidance, Ee W/m Illuminance Ev lm/m Input power per unit area Irradiance Lux, lx Radiant energy Qe Ws Luminous energy Qv lm s Power * time 2 2 Irradiation He Ws/m Illumination Hv lm s/m Radiant energy or luminous energy per unit area

3.2 Data sheet construction Data sheet information is generally These define maximum permissible D control settings presented in the following sequence: operational and environmental D load conditions conditions. If any one of these D Device description conditions is exceeded, this could D drive level D Absolute maximum ratings result in the destruction of the device. D environmental conditions and the D Thermal data – Thermal Unless otherwise specified, an properties of the devices resistances ambient temperature of 25$3_C is themselves (i.e. ageing). assumed for all absolute maximum D Optical and electrical ratings. 3.2.3 Thermal data – thermal characteristics resistances Most absolute ratings are static D Diagrams characteristics; if measured by a pulse Some thermal data (e. g. junction D Dimensions (Mechanical data) method, then the associated temperature, storage temperature measurement conditions are stated. range, total power dissipation), 3.2.1 Device description Maximum ratings are absolute (i. e. because they impose a limit on the not interdependent). application range of the device, are The following information is given under the heading ”Absolute Any equipment incorporating provided: Type number, maximum ratings”. semiconductor materials used, semiconductor devices must be sequence of zones, technology used, designed so that even under the most The thermal resistance junction device type and, if necessary unfavorable operating conditions the ambient (RthJA) quoted is that which construction. specified maximum ratings of the would be measured without artificial devices used are never exceeded. cooling, i.e. under the worst Also, short-form information on These ratings could be exceeded conditions. special features and the typical because of changes in applications is given. Temperature coefficients, on the other D supply voltage, the properties of hand, are listed together with the 3.2.2 Absolute maximum other components used in the associated parameters under ”Optical ratings equipment and electrical characteristics”.

30 TELEFUNKEN Semiconductors

3.2.4 Basic characteristics characteristics. Radiant sensitive or emitting area respectively being typical, all other Under this heading optical and 3.2.6 Dimensions dimensions are maximum. electrical characteristics and (Mechanical data) Any device accessories must be switching characteristics are grouped It contains important dimensions, as the most important operational ordered separately, quoting the order sequence of connection supplemented number. characteristics (minimum, typical and by a circuit diagram. Case outline maximum values) together with drawings carry DIN-, JEDEC or Preliminary specifications associated test conditions commercial designations. supplemented with curves, an Information on angle of sensitivity or This heading indicates that some AQL-value being quoted for intensity and weight completes the list information on the device concerned particularly important parameters. of mechanical data. may be subject to slight changes. 3.2.5 Family of curves Note especially: Not for new developments If the dimensional information does Besides the static (dc) and dynamic This heading indicates that the device not include any tolerances, then the (ac) characteristics, family of curves concerned should not be used in following applies: are given for specified operating equipment under development, it is, conditions. They show the typical Lead length and mounting hole however, available for present interdependence of individual dimensions are minimum values. production.

Luminance; terms, conversion factors

Unit cd/m2 cd/ft2 cd/in2 asb sb L fL Lumen/sr Lumen/sr Lumen/sr Apostilb Stilb Lambert Foot- m2 ft2 in2 lambert cd/m2 1 9.29*10–2 6.454*10–4 p 10–4 p*10–4 0.2919 cd/ft2 10.764 1 6.94*10–3 33.82 1.076*10–3 3.382*10–3 p cd/in2 1550 144 1 4869 0.155 0.4869 452.4 asb 1/p 2.957*10–2 2.054*10–4 1 10–4/p 10–4 0.0929 sb 104 929 6.452 p*104 1 p 2919 L 104/p 2.957*102 2.054 104 1/p 1 929 fL 3.426 1/p 2.211*10–3 10.764 3.426*10–4 1.0764*10–3 1

Illuminance; terms, conversion factors

Unit Lux, lx lm/cm2 fc (Lumen/m2) Lumen/cm2 Footcandle Lux, lx 1 10–4 0.0929 lm/cm2 104 1 929 Footcandle, fc 10.764 10.764*10–4 1

31 TELEFUNKEN Semiconductors

4. Physics and technology 4.1 Emitters and Mg, n-type conductivity with of the solution. Several layers elements of valency six, such as S, Se differing in composition may be 4.1.1 Materials and Te. However, silicon, of valency obtained using different solutions one four, can occupy sites of III-valence after another, as needed e.g. for DHs. Infrared emitting diodes (IREDs) can and V-valence atoms, and, therefore, be fabricated from a range of different acts as donor and as acceptor. The In liquid phase epitaxial reactors, III-V compounds. Unlike the conductivity type depends primarily production quantities of up to 50 elemental semiconductor silicon, the on the material growth temperature. wafers with several layers can be compound III-V semiconductors Therefore – by exact temperature handled. consists of two different elements of control – pn junctions can be grown group three (e.g., Al, Ga, In) and five with the same doping species Si on (e.g., P, As) of the periodic table. The both sides of the junction. Ge, on the 4.1.2 IRED chips and bandgap energies of these compounds other hand, has also a valency of four, vary between 0.18 eV and 3.4 eV. but occupies group V sites at high characteristics temperatures i.e. p-type. However, the IREDs considered here At present the most popular IRED emit in the near infrared spectral chip is made only from GaAs. The range between 800 nm and 1000 nm, Only monocrystalline material is used structure of the chip is displayed in and, therefore, the selection of for IRED production. In the mixed figure 4.1a. materials is limited to GaAs and the crystal system Ga1-XAlXAs, mixed crystal Ga1-XAlXAs, 0vXt0.8, the lattice constant varies p - GaAs : Si 0vXt0.8, made from the pure only by about 1.5@10–3. Therefore, Al compounds GaAs and AlAs. monocrystalline layered structures of different Ga Al As compositions Infrared radiation is produced by 1-X X can be produced with extremely high radiative recombination of electrons structural quality. These structures are and holes from the conduction and useful because the bandgap can be valence bands. The emitted photon shifted from 1.40 eV (GaAs) to values energy, therefore, corresponds closely beyond 2.1 eV. In this way transparent to the bandgap energy E . The g windows and heterogeneous emission wavelength can be 94 8200 structures can be fabricated. calculated according to the formula Transparent windows are another l = 1.240 mm eV/E . The internal g suitable means to increase efficiency, efficiency depends on the band and heterogeneous structures can Au : Ge n - structure, the doping material and the provide shorter switching times and doping level. Direct bandgap higher efficiency. Such structures are materials offer high efficiencies, termed double heterostructures (DH) ca. 470 mm because no photons are needed for and consist normally of two layers recombination of electrons and holes. that confine a layer with a much GaAs is a direct gap material and smaller bandgap. Figure 4.1a Ga1-XAlXAs is direct up to X = 0.44. The doping species Si provides the best efficiencies and shifts the The best production method for all On an n-type substrate, two Si-doped emission wavelength below the materials needed is liquid phase layers are grown by liquid phase bandgap energy into the infrared epitaxy (LPE). This method uses epitaxy from the same solution. spectral range by about 50 nm Ga-solutions containing As, possibly Growth starts as n-type at high typically. Al, and the doping substance. The temperature and becomes p-type solution is saturated at high below about 820°C. A structured Charge carriers are injected into the temperature, typically 900°C, and Al-contact on the p-side and a large material via pn junctions. Junctions of GaAs substrates are dipped into the area Au:Ge contact on the back side high injection efficiency are readily liquid. The solubility of As and Al provide a very low series resistance. formed in GaAs and Ga1-XAlXAs. decreases with decreasing The angular distribution of the P-type conductivity can be obtained temperature. Therefore epitaxial emitted radiation is displayed in with metals of valency two, such as Zn layers can be grown by slow cooling figure 4.1b.

31 TELEFUNKEN Semiconductors

0° 30° Au : Ge / Au whereas the back side metallization is Au:Zn. The angular distribution of the emitted radiation is displayed in figure 4.2b.

0° 30° 94 8201 94 8197 0204060 Au : Zn p - Ga

Figure 4.1b ca. 370 mm The package of the chip has to provide a good collection efficiency of the radiation emitted sideways, and has to 94 8198 Figure 4.2a 0204060 diminish the refractive index step between the chip (n = 3.6) and the air Originally the GaAs substrate was Figure 4.2b (n = 1.0) with an epoxy of refractive adjacent to the n-side. Growth of The Ga Al As chip described has index 1.55. In this way the output Ga0.7Al0.3As started as n-type and 1-X X power of the chip is increased by a became p-type – as in the first case – one of the highest output powers of factor of 3.5 for the assembled device. through the specific properties of the any chip available. Due to its shorter doping material Si. A characteristic wavelength, the chip offers specific The chip described is the most feature of the Ga-Al-As phase system advantages in combination with a Si cost-efficient chip. The forward causes the Al-content of the growing detector. Integrated Opto-ICs, like voltage at IF = 1.5 A has the lowest epitaxial layer to decrease. Therefore amplifiers or Schmitt Triggers, have possible value. The total series the Al-concentration at the junction higher sensitivities at shorter resistance is typically only 0.60 W. wavelengths. Similarly, has dropped to 8% (Ga0.92Al0.08As), The output power and the linearity producing an emission wavelength of phototransistors are also more (defined as the optical output power 880 nm. During further growth the sensitive. Finally the frequency increase divided by the current Al-content approaches zero. The bandwidth of pin diodes is higher at increase between 0.1 and 1.5 A) are gradient of the Al-content, and shorter wavelengths. Another high. Relevant data on the chip and a therefore, also of the bandgap energy, important advantage of this chip is its typical assembled device are given in produces an emission band of a high linearity up to and beyond 1.5 A. table 4.1. relatively large half width. The The forward voltage, however, is higher than the voltage of a GaAs The technology used for another chip transparency of the large bandgap material results in a very high external chip. Table 4.1 provides more data on eliminates the absorbing substrate and the chip. uses only a thick epitaxial layer. The efficiency on this type of chip. chip is shown in figure 4.2a. The chip is mounted n-side up, and the front side metallization is Au:Ge/Au,

32 TELEFUNKEN Semiconductors

A technology combining some of the Starting with the n-type substrate, n- Figure 4.3b advantages of the two technologies and p-type GaAs layers are grown in described above is summarized in a manor similar to the epitaxy of the This chip type combines a relatively figure 4.3a. standard GaAs:Si diode. After this, a low forward voltage with a high highly transparent window layer of electro-optical efficiency, offering an Ga Al As, doped p-type with Ge, is 1-X X optimized combination between the p - GaAlAs : Ge grown. The upper contact to the p-side advantageous characteristics of the p - GaAs is made of Al and the back side Al two other chips. Refer again to contact is Au:Ge. The angular table 4.1 for more details. distribution of the emitted radiation is shown in figure 4.3b.

1000

100 94 8202

Au : Ge n - Ga 1 e I – Radiant Intensity ( mW/sr ) ca. 420 mm 0.1 Figure 4.3a 100 101 102 94 8189 e IF – Forward Current (

Table 4.1. Characteristic data of IRED chips

Technologygy Typical chip data Typicalyp Typical device data didevice Fe/mW lp/nm Dl/nm Polarity Fe/mW Fe/mW UF/V UF/V Fe(1.5A)/ at 0.1 A at 0.1 A at 1.5 A at 0.1 A at 1.5 A Fe(0.1A) GaAs 4.3 950 50 p up TSUS 540. 15 140 1.3 2.1 9 on GaAs Ga1-XAlXAs 6.7 875 80 n up TSHA 550. 27 350 1.5 3.4 13 GaAs + 5.8 950 50 p up TSIP 520. 24 300 1.3 2.4 12 Ga1-XAlXAs on GaAs

33 TELEFUNKEN Semiconductors

4.2 UV, visible, and near Figure 4.4. Absorption and penetration depth of optical radiation IR silicon in silicon Re photodetectors Depending on the wavelength, the hn (adapted from ”Sensors, Vol 6, penetration depth varies from tenths Optical Sensors, Chapt. 8, VCH – of a micron at 400 nm (blue) to more µ µ Verlag, Weinheim 1991) than 100 m at 1 m (IR). For detectors to be effective, an Energy 4.2.1 Silicon photodiodes interaction length of at least twice the penetration depth should be realized 4.2.1.1The physics of silicon 2 detector diodes (equivalent to 1/e = 86% absorbed radiation). In the pn diode, the The absorption of radiation is caused generated carriers are collected by the 0 by the interaction of photons and the electrical field of the pn junction. The Figure 4.5. charge carriers inside a material. The effects in the vicinity of a pn junction Generation-recombination effects in different allowed energy levels and are shown in figure 4.8 for various the vicinity of a pn junction. Top: the band structure determine the types and operating modes of the pn Short circuit mode, bottom: reverse likelihood of interaction and, diode. The incident radiation biased therefore, the absorption generates mobile minority characteristics of the semiconductors. carriers-electrons in the p-side, holes The long wavelength cutoff of the in the n-side. In the short circuit mode The recombination takes place inside absorption is given by the bandgap shown in figure 4.5 (top), the carriers the bulk material with technology and energy. The slope of the absorption will drift under the field of the built-in process dependent time constants curve depends on the physics of the potential of the pn junction. Other which are very small near the contacts interaction and is, for silicon, much carriers diffuse inside the field-free and the surfaces of the device. For weaker than for most other semiconductor along a concentration short wavelengths with very small semiconducting materials. This gradient, resulting in an electrical penetration depths, the carrier results in the strongly current through the applied load, or recombination is the efficiency wavelength-dependent penetration without load, in an external voltage, limiting process. To achieve high depth which is shown in figure 4.4. resulting in the open circuit voltage efficiencies, as many carriers as (The penetration depth is defined as VOC, at the contact terminals. The possible should be separated by the that depth where 1/e of the incident bending of the energy bands near the electrical field inside the space charge radiation is absorbed.) surface is caused by surface states. An region. This is a very fast process, equilibrium is established between much faster than the typical the generation, the recombination of recombination times (for data, see 105 carriers, and current flow through the chapter 4.2.4.3). The width, W, of the load. space charge is a function of the –1 104 doping concentration NB and the Surface States applied voltage V: Si wi 103 å ) + Ǹ2 s (Vbi V) W q NB n 102 h

101 Energy Absorption Coefficient ( cm ) Absorption Coefficient

100 0.4 0.6 0.8 m 94 8595 Wavelength ( m 0

34 TELEFUNKEN Semiconductors

(for a one-sided abrupt junction), Antireflection characteristic of a standard rectifier Coating where Vbi is the built-in voltage, es the diode. The relationship between dielectric constant of Si, and q the p+ current, I, and voltage, V, is given by Contact electronic charge. The capacitance of Space Cha + ń the diode, which can be speed I IS (expV VT–1) (2.1) limiting, is also a function of space with VT = kT/q charge width and applied voltage and k = 1.38 * 10–23 JK–1, is given by Boltzmann constant –19 n X1...10 Wcm q = 1.6 * 10 As, å A C + s (1.2) electronic charge. W n+ Is, the dark reverse saturation current, where A is the area of the diode. An is a material and technology externally applied bias will increase dependent quantity. The value is the space charge width (see figure Contact influenced by the doping 4.2b) with the result that a larger concentrations at the pn junction, by number of carriers are generated p+ the carrier lifetime, and especially by inside this zone which can be swept the temperature. It shows a strongly out very fast with high efficiency exponential temperature dependence under the applied field. From and doubles every 8°C. equation 1.1, it is evident that the Space Charge space charge width is a function of the doping concentration NB. Diodes with i n: . a so called pin structure show a wide I space charge width where i stands for n+ intrinsic, very low doped. This zone is also sometimes nominated as n or p rather than low doped n, n- or p, p-zone indicating the very low Figure 4.6. Comparison of pn diode F doping. e=0 (a) and pin diode (b) IF1 In figure 4.6 the different behavior of 4.2.2 Properties of silicon low doped pin diodes and pn diodes is photodiodes shown. The space charge width of the pin diode (b) with a doping level (n=N ) as low as N = 5*1011 cm–3 is 4.2.2.1 I-V Characteristics of B B Fe about 80 µm wide for a 2.5 V bias in illuminated pn junction 94 8600 IS comparison with a pn diode with a 15 –3 The I-V-characteristics of a doping (n) of NB = 5*10 cm with µ photodiode are shown in figure 4.7. Figure.4.7a. I-V-Characteristics of an only 0.8 m. The characteristic of the non Si photodiode under illumination. illuminated diode is identical to the Parameter: Incident radiant flux

35 TELEFUNKEN Semiconductors

Dependent on load resistance, RL, and 4.2.2.2 Spectral responsivity 94 8601 applied bias, one can distinguish 4.2.2.2.1 Efficiency of Si different operating modes. The photodiodes unbiased diode operates in the photovoltaic mode. Under short The spectral responsivity, sl, is given circuit conditions (load RL = 0 W), the as the number of generated charge short circuit current, ISC will flow into carriers (h*N) per incident photons N the load. When RL increases to of energy h*n (h is the percent

Forward Current ( nA ) Forward Current ( nA infinity the output voltage of the diode efficiency, h is Plancks constant, and Reverse Voltage ( mV ) will rise to the open circuit voltage, n is the frequency of radiation). Each –160 –120 –80 –40 VOC, given by photon will at most generate one –2 charge carrier. The photocurrent Ire + l f ń then, is VOC VT ln (s( ) e –4 Ire + h N q Because of this logarithmic behavior, + ńf the open circuit voltage is often used sl Ire e for optical lightmeters in Figure 4.7b. Measured + h N qń(h n N) I-V-characteristics of an Si photographic applications. The open circuit voltage shows a strong photodiode (as example S 206 P) in l(mm) ƪ ƫ sl + AńW the vicinity of the origin temperature dependence with a 1.24 negative temperature coefficient. The reason for this is the exponential With fixed efficiency, a linear Typical dark currents of Si temperature coefficient of the dark relationship between wavelength and spectral responsivity is valid. photodiodes are dependent on size reverse saturation current Is. For and technology and range from less precise light measurement, a Figure 4.4 shows that semiconductors than picoamps up to tens of nanoamps temperature control of the photodiode absorb radiation similar to a cutoff at room temperature conditions. As is employed. Precise linear optical filter. At wavelengths smaller than the noise generators, the dark current Ir0 power measurements require small cutoff wavelength the incident and the shunt resistance Rsh (defined voltages at the load typically smaller radiation is absorbed. At larger and measured at a voltage of 10 mV than about 5% of the corresponding wavelengths the radiation passes forward or reverse, or peak to peak) open circuit voltage. For less precise through the material without are limiting quantities when detecting measurements, an output voltage of interaction. The cutoff wavelength very small signals. half the open circuit voltage can be corresponds to the bandgap of the The photodiode exposed to optical allowed. The most important material. As long as the energy of the disadvantage of operating in the radiation generates a photocurrent Ir photon is larger than the bandgap, exactly proportional to the incident photovoltaic mode is the relative large carriers can be generated by response time. For faster response, it radiant power Fe. The quotient of absorption of photons, provided that both is the spectral responsivity s(l), is necessary to implement an the material is thick enough to additional voltage source reverse propagate photon-carrier interaction. l + ńf ƪ ń ƫ s( ) Ir e A W (2.2)biasing the photodiode. This mode of Bearing in mind that the energy of operation is termed the The characteristics of the irradiated photons decreases with increasing photoconductive mode. In this mode, photodiode is then given by wavelength, it can be understood, that the lowest detectable power is limited the curve of the spectral responsivity + ń l I IS (expV VT–1) –s( ) by the shot noise of the dark current, vs. wavelength in the ideal case Is, while in the photovoltaic mode, the (100% efficiency) will have a and in the case V[0, zero or reverse thermal (Johnson) noise of the shunt triangular shape (see figure 4.8). For bias we find, resistance, Rsh, is the limiting silicon photodetectors, the cutoff quantity. I + –Is–s(l) fe wavelength is near 1100 nm.

36 TELEFUNKEN Semiconductors

In most applications it is not necessary 4.2.2.2.2 Temperature dependence In the literature remarks can be found to detect radiation with wavelengths of spectral on instabilities of detectors in the larger than 1000 nm. Therefore, responsivity blue, UV, and near IR under certain designers work with a typical chip conditions. Thermal cycling has The efficiency of carrier generation thickness of 200 µm to 300 µm, reversed the degradation effects. by absorption and the loss of carriers which results in reduced sensitivity at Surface effects and contamination are by recombination are the factors wavelengths larger than 950 µm. possible causes but are which influence the spectral With a typical chip thickness of 250 technologically well controlled. responsivity. The absorption µm, an efficiency of about 35% at coefficient increases with 4.2.2.2.5 Angular dependence of 1060 nm is achieved. At shorter temperature. Radiation of long responsivity wavelengths (blue-near UV, 500 nm wavelength is, therefore, more to 300 nm) the sensitivity is limited by The angular response of Si efficiently absorbed inside the bulk, recombination effects near the surface photodiodes is given by the optical resulting in increasing response. For of the semiconductor. The reduction laws of reflection. The angular shorter wavelengths (< 600 nm), in the efficiency starts near 500 nm response of a detector is shown in reduced efficiency is observed with and increases with decreasing figure 4.9. increasing temperature because of wavelength. Standard detectors increased recombination rates near designed for visible and near 0° the surface. These effects are strongly 1.0 IR radiation may have only poor dependent on technological UV/blue sensitivity and poor UV A/W parameters and therefore cannot be stability. Well designed sensors for 0.8 generalized to the behavior at longer wavelengths of 300 to 400 nm can wavelengths. operate with fairly high efficiencies. 0.6 At smaller wavelengths (< 300 nm) 4.2.2.2.3 Uniformity of spectral responsivity Acm2/W the efficiency decreases strongly. 0.4 Inside the technologically defined 1.0 active area of photodiodes, the 0.2 spectral responsivity shows a variation of the sensitivity on the 0.8 94 8603 order of < 1%. Outside the defined 0 –90° –60° –30° 0 0.2 0.4 active area, especially at the lateral 0.6 edges of the chips, the local spectral Angle Relative R response is sensitive to the applied 0.4 reverse voltage. Additionally, this Figure 4.9. Responsivity of Si effect depends on the wavelength. photodiodes as a function of the angle Therefore, the relation between of incidence 0.2 Spectral Responsitivity ( A/W ) A/W Spectral Responsitivity ( power (Watt) related spectral responsivity, sl (A/W), and power The semiconductor surfaces are 0 density (Watt/cm2) related spectral covered with quarter wavelength 400 600 800 responsivity, sl [A/(W/cm2)] is not a antireflection coatings. The 94 8602 Wavelength ( nm constant. This relation is a function of encapsulation is performed with wavelength and reverse bias. uncoated glass or sapphire windows. 4.2.2.2.4 Stability of spectral Figure 4.8. Spectral responsivity as a The bare silicon response can be responsivity function of wavelength of a Si altered by optical imaging devices photodetector diode, ideal and typical Si detectors for wavelengths between such as lenses. In this way nearly values 500 nm and 800 nm appear to be every arbitrary angular response can stable over very long periods of time. be achieved.

37 TELEFUNKEN Semiconductors

4.2.2.3Dynamic properties of Si the order of 10 ps/µm for electrons in operating reverse-bias voltage is photodiodes p-material. With a 10 µm drift region, usually between 130 and 300 V and travelling times of 100 ps can be must be very well controlled by a gain Si photodiodes are available in many expected. The response time is a control circuit because of the large different variations. The design of the function of the distribution of the temperature coefficient of the diodes can be tailored for special generated carriers and is, therefore, multiplication factor. Sometimes, purposes. Si photodiodes may be wavelength dependent. instead of a gain control, a designed for maximum efficiency at temperature stabilization of the APD given wavelengths, for very low The diffusion of carriers is a very slow is used. leakage currents, or for high speed. process. The time constants are on the The design of a photodiode is nearly order of some µs. The typical pulse always a compromise between response of detectors is dominated by n+ various aspects of a specification. these two processes. Obviously, + carriers should be absorbed in large Inside the absorbing material of the space charge regions with high diode, photons can be absorbed in internal electrical fields. This requires different regions. For example at the material with an adequate low doping top of a p+n– -Diode there is a highly level. Furthermore, a reverse bias of doped layer of p+–Si. Radiation of rather large voltage is useful. shorter wavelengths will be Radiation of shorter wavelength is – p effectively absorbed, but for larger p ( ) absorbed in smaller penetration wavelengths only a small amount is depths. At wavelengths shorter than absorbed. In the vicinity of the pn + 600 nm, decreasing wavelength leads p junction there is the space charge to an absorption in the diffused top region, where most of the photons layer. The movement of carriers in should generate carriers. An electric this region is also diffusion limited. field accelerates the generated carrier Because of small carrier lifetimes, the – in this part of the detector to a high time constants are not as large as in drift velocity. The carriers which are homogeneous substrate material. not absorbed in these regions will Figure 4.10. Avalanche photodiode, Finally, the capacitive loading of the penetrate into the field-free region, cross section. output in combination with the load where the motion of the generated resistance limits the frequency carriers fluctuates by the slow response. 4.2.3.2 Phototransistors diffusion process. The phototransistor is equivalent to a The dynamic response of the detector photodiode in conjunction with a is composed of the different processes 4.2.3 Characteristics of other bipolar transistor amplifier (figure which transport the carriers to the silicon 4.11). Typically, current contacts. The dynamic response of photodetectors amplification, B, is between 100 and photodiodes is influenced by three 4.2.3.1 Avalanche photodiodes 1000 depending on the type and fundamental effects: application. The active area of the In Avalanche photodiodes (APD) the 1. Drift of carriers in an electric field phototransistor is usually about reverse bias voltage can be increased 0.5*0.5 mm2. Data of spectral 2. Diffusion of carriers to a value where multiplication of responsivity are equivalent to those of carriers starts by impact ionization. 3. Capacitance * load resistance photodiodes, but must be multiplied The amplification M can rise up to a by the factor of the current The carrier drift in the space charge factor of thousands, but typical amplification, B. region occurs rapidly with very small working points are between M = 50 time constants. Typically, the transit and M = 200. The current The switching times of times in an electric field of 0.6 V/µm gain-bandwidth product can be on the phototransistors are dependent on the are in the order of 16 ps/µm and order of 200 GHz. Therefore, APDs current amplification and load 50 ps/µm for electrons and holes, can be used with frequencies of up to resistance and are between 30µs and respectively. At the (maximum) some gigahertz. A typical structure of 1µs. The resulting cutoff frequencies saturation velocity, transit time is on an APD is shown in figure 4.10. The are a few hundred Kilohertz.

38 TELEFUNKEN Semiconductors

The transit times, tr and tf, are given Different applications require 4.2.4.1 Equivalent circuit by specialized detectors and also special Photodetector diodes can be Ǹ 2 2 2 circuits for optimized function. described by the electrical equivalent t + (1ń2ft ) ) b(RC V) r,f B circuit shown in figure 4.12. ft: Transit frequency R: Load resistance Ish CB: Base-collector capacitance, Id b= 4...5 Iph V: Amplification VD The most frequent application of Rsh phototransistors is found in interrupters and opto-isolators. Antireflection Coating Metallization Isolatio Emitter Base Figure 4.12 + IO Iph–ID–Ish qV I + I –I (exp D –1)–I O ph s kT sh l f n p + s( ) e–Ish ) VOC VT ln ( 1) n Is As described in chapter 4.2, the n+ incident radiation generates a photocurrent loaded by a diode 94 8605 characteristic and the load resistor, Backside Contact RL. The other parts of the equivalent circuit (the parallel capacitance, C, Figure 4.11. Phototransistor, cross combined from junction, Cj, and stray section and equivalent circuit capacitances, the serial resistance, RS, 4.2.4 Applications and the shunt resistance, Rsh, representing an additional leakage) Silicon photodetectors are used in can be neglected in most of the manifold applications, such as sensors standard applications, and are not for radiation from the near UV over expressed in equations 2.3 and 2.4. the visible to the near infrared. There However, at the limits of the field of are numerous applications in the application, high frequencies or measurement of light, such as extreme irradiation levels, these parts dosimetry in the UV, photometry, and must be regarded as limiting radiometry. A well known application elements. is shutter control in cameras. 4.2.4.2 Searching for the right Another large application area for detector diode type detector diodes and especially phototransistors, is that of position The photodiode BPW 20 R is a pn sensing. Examples are quadrant diode based on rather highly doped detectors, differential diodes, n-silicon, while the S 153 P is a pin interruptors, and reflex sensors. diode based on very lightly doped n-silicon. Both diodes have the same Other types of silicon detectors are active area and the spectral response, built-in as parts of optocouplers, or as a function of the wavelength, is optoisolators. very similar. The difference arises in One of the biggest application areas, the junction capacitance and shunt by numbers, is the remote control of resistance, both of which can TV sets and other home entertainment influence the performance in the appliances. application.

39 TELEFUNKEN Semiconductors Detecting very small signals is the parameters are very well controlled diodes are offset by higher domain of the pn diodes with their on all TEMIC photodetectors. capacitances and smaller bandwidths very small dark currents and in comparison to pin diodes. The very small leakage currents of pn dark/shunt resistances. With a specialized detector technology, these

40 TELEFUNKEN Semiconductors

Often, especially in light meters, of the diode (e.g., using a Peltier Figure 4.14. Dark reverse current vs. photodiodes are operated in the cooler) should be implied. At elevated temperature photovoltaic mode, as depicted in the temperatures, the dark current is circuit of figure 4.13, where a strong increased (see figure 4.14) leading to logarithmic dependence of the open a non-logarithmic and temperature 400 circuit voltage on the input signal is dependent output characteristic (see 10p A used. figure 4.15). The curves shown in figure 4.14 represent the typical 300 100 pA R1 behavior of these diodes. The guaranteed leakage (dark reverse 200 current) is specified with Iro = 30 nA 1nA forV0 the standard types. This value is far from that typically measured. Tighter

Open Circuit Voltage ( mV ) ( mV Voltage Open Circuit 100 R2 customer specifications are available on request. The curves of figure 4.15 30 nA show the open circuit voltage as a 0 94 8607function of the irradiance with the 0.01 0.1 1 10 dark reverse current, IS, as parameter 94 8609 Irradiance ( mW ) [ ƪ ) ń ƫ (in a first approximation increasing IS VO VOC 1 R1 R2 with and Ish have the same effect). The Figure 4.15. Open circuit voltage vs. + l f ń ) parameter covers the possible spread VOC VT ln (s( ) e Is 1) irridiance, parameter: dark reverse of dark current. In combination with current, BPW 20 R Figure 4.13. Photodiode in the figure 4.14 one can project the photovoltaic mode operating with a extreme dependence of the open voltage amplifier circuit voltage at high temperatures. 400

7 It should be noted that the extremely 10 high shunt/dark resistance (more than Reverse Bias 300 15 GΩ) combined with a Voltage Vr=20V 5 high-impedance operational 10 200 amplifier input and a junction capacitance of about 1 nF can result in 103 slow switching off time constants of 100 BPW ) ( mV Voltage Open Circuit some seconds. Some instruments, ) Current ( nA therefore, have a reset button for 1 shortening the diode before starting a 10 0 measurement. The photovoltaic mode 0204060 of operation for precise 94 8610 Temperature ( °C 10–1 measurements should be limited to –200 20 60 100 the range of low ambient Figure 4.16. Open circuit voltage vs. 94 8608 Temperature ( °C temperatures or a temperature control temperature, BPW46

41 TELEFUNKEN Semiconductors

4.2.4.3 Operating modes and Figure 4.17a. Transimpedance Figure 4.18 shows photocurrent circuits amplifier, current to voltage flowing into an RC load, where C converter, short circuit mode represents the junction and stray The advantages and disadvantages of capacitance while R3 can be a real or operating a photodiode in the open Vb complex load, such as a resonant circuit mode have been discussed. circuit for the operating frequency. R For operation in the short circuit (see Vb figure 4.17) or photoconductive (see figure 4.18) mode, current-to-voltage converters are typically used. In V0 comparison with the photovoltaic C2 mode, the temperature dependence of 94 8612 the output signal is much lower. Generally, it can be stated that the temperature coefficient of the light Figure 4.17b. Transimpedance reverse current is positive for amplifier, current to voltage R C 1 irradiation with wavelengths converter, reverse biased photodiode 1 R3 R2 > 900 nm, growing with increasing wavelength. For wavelengths < 600 nm, a negative temperature The circuit in figure 4.17a minimizes [ f l ƪ ) coefficient is found, likewise with the effect of the reverse dark current VO e s( ) R3 1 increasing absolute value to shorter while the circuit in figure 4.17b improves the speed of the detector Figure 4.19. AC-coupled amplifier wavelengths. Between these circuit wavelength boundaries the output is diode due to a wider space charge nearly independent of temperature. region with decreased junction Using this mode of operation, reverse capacitance and field increased The circuit in figure 4.19 is equivalent biased or unbiased (short circuit velocity of the charge carrier to figure 4.18 with a change to AC conditions), the output voltage, Vo, transport. coupling. In this case, the influence of will be directly proportional to the the background illumination can be Vb incident radiation, φe (see the separated from a modulated signal. equation in figure 4.17a). The relation between input signal (irradiation, φe) and output voltage is given by the equation in figure 4.19.

R 4.2.4.4 Frequency response The limitations of the switching times

V0 in pn diodes is determined by the carrier lifetime. Due to the absorption R1 properties of silicon, especially in pn C R3 R2 diodes, most of the incident radiation 94 8611 at longer wavelengths is absorbed outside the space charge region. + F l Therefore, a strong wavelength VO –R e s( ) Figure 4.18. RC-loaded photodiode dependence of the switching times + VO –ISC R with voltage amplifier can be observed (figure 4.20).

42 TELEFUNKEN Semiconductors

30 94 8615

tr =0V t =0V 20 f m tr= –10V

tf = –10V

15 rf

10 Risetime t , Falltime ( s )

0 550 600 650 700 750 800 850 900 950 Wavelength ( nm ) Figure 4.20. Switching times vs. wavelength for photodiode BPW 20 R

A drastic increase in rise and fall times parameter: load resistance, l = 820 is observed at wavelengths > 850 nm. 12 nm R = 100kW The differences between unbiased and L biased operation result from the 10 W widening of the space charge region. 10k However, for the pin diodes (BPW 34 8 / S 153 P family) similar results with 1 shifted time scales are found. This 6 behavior, in this case in the frequency domain, is presented in figure 4.21 for ) V Reverse Bias ( 4 a wavelength of 820 nm and figure 4.22. for 950 nm. 2

0 104 105 106 94 8616 – 3 dB - Bandwidth (

Figure 4.21. BPW 41-family, bandwidth vs. reverse bias voltage,

43 TELEFUNKEN Semiconductors Figure 4.22. BPW 41-family, Additionally, the influence of the load 12 bandwidth vs. reverse bias voltage, resistances and the reverse bias parameter: load resistance, l = 950 voltages can be taken from these 10 nm diagrams. R =1MW W 8 L 1k Below about 870 nm only a small 100kW 10kW wavelength dependence can be 6 recognized while a steep change of cut-off frequency takes place from 50

Reverse Bias ( V ) V Reverse Bias ( 4 870 nm to 950 nm (different time scales in figure 4.21 and figure 4.22!). 2

0 103 104 105 94 8617 – 3 dB - Bandwidth (

44 TELEFUNKEN Semiconductors

For cutoff frequencies greater 10–20 designs, we are able to supply pin The main applications for these MHz, depending on the supply diodes with cutoff frequencies up to 1 photodiodes are found in optical local voltage available for biasing the GHz at only a 3 V bias voltage with area networks operating in the first detector diode, pin diodes are also only an insignificant loss of optical window at wavelengths of used. However, for this frequency responsivity. 770 nm to 880 nm. range, and especially when operating For operating these fast diodes in 4.2.4.5 Which type for which with low bias voltages, thin combination with current voltage application? epitaxially grown intrinsic (i) layers converters, transimpedance In table 4.2 selected diode types are are incorporated in the pin diodes. As amplifiers, signal regenerators and assigned to different applications. For a result, these diodes (e.g., TEMICs LED drivers are available from more precise selection according to BPW 97) can operate with low bias TEMIC (Transimpedance amplifier: chip sizes and packages refer to the voltages (3 to 4 V) with cutoff U 6791, regenerator: U 6792, and tables on the introductory pages of frequencies of 300 MHz at a LED driver: U 6795). this data book. wavelength of 790 nm. With application specific optimized

Table 4.2 Diode reference table Detector application pin diode pn diode epi-pin diode Photometry, Lightmeter BPW 21 R Radiometry S 153 P, BPW 34, ... BPW 20 R Light barriers BPW 24 Remote control BPW 34, BPW 46, BPV 10 Low speed data transmission < 10 MHz, clear package IR filter for BPV 20 F–BPV 23 F, l > 900 nm included BPW 41 N, S 186 P, BPV 10 F, S 288 P, TFM-Series (with integrated amplifier and demodulator) IR filter for BPV 23 NF, BPW 82, BPW 83 l > 820 nm included Fiber optical receiver frequencies < 20 MHz high frequencies BPW 88, BPW 24 BPW 97, BPW 98 Densitometry BPW 34, BPV 10, BPW 43 BPW 20 R, BPW 21 R Quadrant detector S 239 P

V 4.2.5 Phototransistors threshold level (see equation 5.1 and 94 8618 s 5.2) R 4.2.5.1 Circuits L + f l VO VS–B e s( ) RL V0 Typically a phototransistor is [ f l ń operated in a circuit as shown in figure VO VS–(B e s( )–0.6 R

4.23. The resistor RB can be omitted RB in most applications. In some For the dependence of the rise and fall phototransistors the base is not times on the load resistance and connected. RB can be used to suppress collector-base capacitance refer to Figure 4.23. Phototransistor with load background radiation by setting a chapter 4.2.3.2. resistor and optional base resistor.

45 TELEFUNKEN Semiconductors 5. Measurement techniques 5.1 Introduction through the device and the voltage a high impedance voltmeter has to be developed across it is measured on a used, or the current consumption of The characteristics of optoelectronics high-impedance voltmeter. the DVM has to be calculated and devices given in the data sheets are added to the specified current. A V = 5V verified either by 100% production S second measurement step will then tests followed by statistic evaluation give correct readings. or by sample tests on typical I = 50mA In the case of GaAs IR diodes, it is specimens. These tests can be divided 100mA into the following categories: constant usual to measure the total radiant output power, Fe. This is done with a a) Dark measurements calibrated large-area photovoltaic cell b) Light measurements fitted in a conical reflector with a bore V c) Measurements of switching F which accepts the test item – see characteristics, cut-off V figure 5.3. An alternate test set uses a frequency and capacitance silicon photodiode attached to an d) Angular distribution Rj integrating sphere. A constant dc or measurements pulsating forward current of specified e) Spectral distribution magnitude is passed through the IR measurements diode. The advantage of pulse current f) Thermal measurements. Figure 5.1 measurements at room temperature _ The dark and light measurements are To measure the reverse voltage, VR, a (25 C) is that the results can be 100% measurements. All other values 10 mA or 100 mA reverse current from reproduced exactly. If, for reasons of are typical. The basic circuits used for a constant current source is impressed measurement economy, only dc these measurements are shown in the through the diode (figure 5.2) and the measurements (figure 5.4) are to be following sections. The circuits may voltage developed across it is made, then the energizing time should be modified slightly to cater for measured on a voltmeter of high input be kept short (below 1 s) and of special measurement requirements. impedance (w10MW). uniform duration, to minimize any fall-off in light output due to internal Most of the test circuits may be VS = 80V ( > V ) heating. simplified by use of a Source Measure R max Unit (SMU), which allows either to Photo Voltaic Cell , Calibrated source voltage and measure current or I = 10 mA constant to source current and measure voltage. 5.2 Dark and light V IF measurements R V 5.2.1 Emitter devices Rj 5.2.1.1 IR diodes (GaAs)

The forward voltage, VF, is measured either on a curve tracer or statically 94 8155 Figure 5.2 using the circuit shown in figure 5.1. Reflector A specified forward current (from a For most devices, VR is specified at 10 constant current source) is passed mA reverse current. In this case either Figure 5.3

44 TELEFUNKEN Semiconductors

VS = 5V optical axis of, the IR diode (figure nanoamperes. The cell must operate 5.5) so that only radiant power of a into an operational amplifier with a narrow axial beam is considered. The high-impedance FET input stage I = 100 mA radiant power within a solid angle of (figure 5.6). Alternately a high constant W = 0.01 steradian (sr) is measured at sensitive electrometer may be used. a distance of 100 mm. The radiant Ik intensity is then obtained by using this 94 8156 Photo Voltaic Ce measured value for calculating the (Calibr radiant intensity for a solid angle of W RL = 1 sr. V W = 0.01 sr 5.2.1.2 Light emitting diodes

RL = 1...10W For forward and reverse voltage measurements (VF and VR respectively) refer to section 5.2.1.1, Figure 5.4 IR diodes. To ensure that the relationship The luminous intensity, I of a light between irradiance and photocurrent v a = 100 mm emitting diode can be calculated by is linear, the photodiode should multiplying the radiant intensity, I , operate near short-circuit e Position of the Emitting Area (figure 5.5) by the absolute eye configuration. This can be achieved sensitivity, K V l (DIN 5031). by using a low resistance load (v10 m ( ) Figure 5.5 This assumes, however, that the W) of such a value that the voltage wavelength of the radiation emitted dropped across it is very much lower VS = 5V by the test item is known exactly. In than the open circuit voltage produced production measurements, a under identical illumination calibrated silicon photovoltaic cell is conditions (R ƠR ).The voltage IF =20mA meas i used in conjunction with a special BPW 20 R ca across the load should be measured constant color filter (e.g., Schott BG 38) which with a sensitive DVM. simulates the red-slope of the eye Knowledge of the radiant intensity, Ie, sensitivity curve. BPW 20 R is used as produced by an IR emitter enables a photovoltaic cell because the short customers to assess the range of IR circuit output current characteristic of light barriers. The measurement this cell is strictly linear even when procedure for this is more or less the the irradiation is very low. This is Ik same as that used for measuring the because the radiant output power of Filter radiant power. The only difference is LEDs is low in comparison with that that in this case the photodiode is used of IR diodes, and the color filter has an Vph = Ik RF ; IV = Ik without a reflector and is mounted at attenuating effect causing the cell to a specified distance from, and on the produce, at the most, only a few Figure 5.6

45 TELEFUNKEN Semiconductors

5.2.2 Detector devices of very small voltage to the Figure 5.9 photodiode and then measuring the 5.2.2.1 Photovoltaic cells, The open circuit voltage, Vo, and short dark current. In case of 10 mV or less, photodiodes circuit current, Ik, of photovoltaic forward and reverse polarity will cells and photodiodes are measured a) Dark measurements result in similar readings. by means of the test circuit shown in The reverse voltage characteristic, VS = 20V figure 5.10. The value of the load VR, is measured either on a curve resistor used for the I measurement E = 0 k tracer or statically using the circuit should be chosen so that the voltage shown in figure 5.7. A dropped across it is low in comparison high-impedance voltmeter, which with the open circuit voltage draws only an insignificant fraction of produced under conditions of I the device’s reverse current, must be ro identical irradiation. used.

VS > VR 10 kW mV 1...10 W I = 100 m Rj R EA = 1klx or cons 2 Ee = 1mW/cm Ik Vo

E = 0 Figure 5.8 VF b) Light measurements 94 8212 Figure 5.10 V The same circuit used in the dark measurement can be used to carry out The light source used for light R measurements is a calibrated light reverse current, Ira, measurements on photodiodes. The incandescent tungsten lamp with no only difference is that the diode is now filters. The filament current is irradiated and a current sampling adjusted for a color temperature of Figure 5.7 resistor of lower value must be used 2856 K (standard illuminant A to DIN Dark reverse current measurements, (figure 5.9), because of the higher 5033 sheet 7), and the specified Iro, must be carried out in complete currents involved. illumination, Ev, (usually 100 or 1000 darkness – the reverse currents of lux) is produced by adjusting the V = 20V silicon photodiodes are of the order of S distance, a, between the lamp and the E = 1klx nanoamperes only, and an A detector on an optical bench. E can Ee = 1mW v illumination of a few lux is quite be measured on a V(l)-corrected lux sufficient to falsify the test result. If a meter, or, if the luminous intensity, Iv, highly sensitive DVM is to be used, of the lamp is known, Ev can be then a current sampling resistor of Ira calculated using the formula: Ev = 2 such a value that the voltage dropped Iv/a . across it is small in comparison with the supply voltage must be connected W in series with the test item (figure 5.8). 10 mV

Under these conditions any reverse Rj = voltage variations of the test samples can be ignored. Shunt resistance (dark resistance) is determined by applying

46 TELEFUNKEN Semiconductors

It should be noted that this inverse filament lamps, consideration should measured in complete darkness square law is only strictly accurate for be given to the following two points: (figure 5.12). Even ordinary daylight point light sources, that is for sources illumination of the wire feed-through D The IR emitter should be where the dimensions of the source glass seals would falsify the connected to a good heat sink to (the filament) are small (v10%) in measurement result. provide sufficient temperature comparison with the distance between stability. source and detector. D dc or pulse current levels as well as VS = 20V Since lux is a measure for visible light pulse duration have great only, near infrared radiation (800 to influence on the self heating of IR 1100 nanometers) where silicon diodes and should be chosen Ico detectors have their peak sensitivity, carefully. E = 0 is not taken into account. D The radiant intensity, I , of the Unfortunately, near infrared emission e device is permanently controlled of filament lamps of different by a calibrated detector. construction varies widely. As a result, light current measurements 5.2.2.2 Phototransistors, 10 kW mV done with different lamps (but the photodarlington transistors same lux and color temperature Ri = The collector emitter voltage, V , calibration) may give readings that CEO is measured either on a transistor differ up to 20%. curve tracer or statically using the 94 8 circuit shown in figure 5.11. Normal The simplest way to overcome this bench illumination does not change problem is to calibrate (measure the the measuring result. light current) some items of a photodetector type with a standard VS = 20V lamp (OSRAM WI41G) and then take Figure 5.12 these devices for adjustment of the Ico lamp used for field measurements. E = 0 The same circuit is used for collector light current, Ica, measurements An IR diode is used as a radiation (figure 5.13), the device being source (instead of the tungsten positioned so that its optical axis incandescent lamp), to measure points towards an incandescent detector devices being used mainly in tungsten lamp with no filters, IR transmission systems together with 10 kW mV producing a standard-A illuminance IR emitters (e.g. IR remote control, IR of 100 or 1000 lx with a color Ri = 1MW headphone). Operation is possible temperature of Tf = 2856 K. both with dc or pulsed current. Alternately an IR irradiance by a 94 8214 GaAs diode is used (refer to the The adjustment of irradiance, Ee, is photovoltaic cells and photodiodes similar to the above mentioned Figure 5.11 section). Note that a lower value adjustment of illuminance, Ev. To In contrast, however, the collector sampling resistor is used, in keeping achieve a high stability similar to the dark current, ICEO or Ico, must be with the higher current involved.

47 TELEFUNKEN Semiconductors

VS = 5V 5.2.3 Coupling devices VS = 5V VS = 5V

a) Dark measurements E = 1 mW/cm2 or Ica e I =10mA I =1m E = 1klx F C A Emitters: For forward and reverse constant con voltage measurements refer to section 5.2.1.1., IR diodes. Detectors: For VCEO and Ico measurements refer to section VCEsat 1...10 W mV 5.2.2.2., phototransistors.

Rjw b) Light measurements

To measure the collector current, IC 9 (figure 5.15), a specified forward Figure 5.13 current, IF, is impressed with the IR Figure 5.16 emitter. Voltage difference is then To measure the collector emitter measured across a low emitter saturation voltage, VCEsat, the device resistance. In the case of collector is illuminated and a constant collector emitter saturation voltage, VCEsat current passed through it. The (figure 5.16), forward current, IF, in magnitude of this current is adjusted the IR diode, and a low collector so that it is less than the minimum current, IC, in the phototransistor, are light current, Ica min, for the same impressed. VCEsat is then measured illuminance (figure 5.14). The (across collector and emitter saturation voltage of the terminals) as shown in the diagram. phototransistor or Darlington stage (approximately 100 mV or 600 mV, respectively) is then measured on a VS = 5V VS = high impedance voltmeter.

IF =10mA IC VS = 5V 20 mA constant

IC = constant

2 Ee = 1 mW/cm or EA = 1klx V CEsat 1 W V

Rjw 94 8217

94 Figure 5.15 Figure 5.14

48 TELEFUNKEN Semiconductors

5.3 Switching Every electronic device introduces a certain delay between input and characteristics output signals as well as a certain 5.3.1 Definition amount of amplitude distortion. The simplified circuit shown in figure 5.17 shows how the input and output signals of opto electronic devices can be displayed on a dual trace oscilloscope.

VS VS

IF Channel II

GaAs-Diode

Channel I Channel II Channel II

94 8219

Figure 5.17 The switching characteristics can be 5.3.2 Notes concerning the because these diodes emit only 1/10 of determined by comparing the timing test set-up the radiant power of IR diodes and of the output current waveform with consequently generate only very low that of the input current waveform The circuits used for testing light signal levels. (figure 5.18). emitting, light sensitive and optically coupled isolator devices are basically 5.3.3 Switching characteristic the same (figure 5.17), the only improvements IF difference being the way in which the on phototransistors and test item is connected in the circuit. 0 darlington It is assumed that the rise and fall phototransistors tp times associated with the signal source (pulse generator) and the dual As in any ordinary transistor, I q trace oscilloscope are insignificant, switching times are reduced if the 1.0 and that the switching characteristics drive signal level, and hence the 0.9 of any light sensitive device used in collector current, is increased. the set-up are considerably shorter Another time reduction (especially in than those of the test item. The fall time tr) can be achieved by use of switching characteristics of light and a suitable base resistor, assuming IR emitters, for example (t ≈ 10 to there is an external base connection, 0.1 r although this can only be done at the 0 1000 ns) are measured with the aid of ≈ expense of sensitivity. tr a pin photodiode as a detector (tr 1 ns). td ts Photo and darlington transistors and photo and solar cells (tr ≈ 0.5 to 50 ms) ton toff are, as a rule, measured by use of fast Figure 5.18 IR diodes (tr < 30 ns) as emitters. GaAsP red light emitting diodes are These time parameters also include used as light sources only for devices the delay that exists in a luminescence which cannot be measured with IR diode between the forward current diodes because of their spectral (IF) and the radiant power (Fe). sensitivity (e.g. BPW 21 R). This is 49 TELEFUNKEN Semiconductors

6. Component construction Infrared components are available in PIN D plastic or metal packages. Plastic Collimating Lens devices, where the chip is mounted PIN-Diode C and bonded on a lead frame, have their main advantage in lower cost and Glass Window enhanced output power or sensitivity. Devices in hermetically sealed packages have better performance in optical and mechanical tolerances and an extended operating temperature range. Black Plastic Package ( IR Filter ) IRED Chip AU Metal Can Package

Reflector

Cathode

94 8315 Plastic Package Anode Cathode

Anode C

50 TELEFUNKEN Semiconductors

7. Tape and reel standards TEMIC TELEFUNKEN Code for taped IREDs Up to 3 consecutive components may microelectronic offers T-1 (3 mm) be missing if the gap is followed by at 3 and T-1 /4 (5 mm) IR emitters and Tape varieties Spacing of leadleast frame 6 components. A maximum of detectors packaged on tape. The A, B, C S: 2.540.5% mm of the components per reel following specification is based on T: 5.08quantity mm may be missing. At least 5 IEC publication 286, taking into empty positions are present at the start account the industrial requirements AS 1 2Zand the end of the tape for tape for automatic insertion. Z:insertion. only for Absolute maximum ratings, fan–foldTensile packing strength of the tape: y 15 N mechanical dimensions, optical and 12: Cathode leaves the reel first 1: Cathode electrical characteristics for taped Pulling force in the plane of the tape, 21: Anode leaves the reel first 2: Anode y devices are identical to the basic at right angles to the reel: 5 N catalog types and can be found in the Figure 7.1 Taping code Note: specifications for untaped devices. Shipment in fan-fold packages are Note that the lead wires of taped 7.1.1 Number of components standard for radial taped devices. components may be shorted or bent in Shipments in reel packing are only accordance with the IEC standard. Quantity per reel: 3 possible, if the customer guarantees mm IRED: 2000 pcs the removal of empty reels. 7.1. Packing 5 We cannot accept the return of reels mm IRED: 1000 pcs according to a German wrapping The tapes of components are available Quantity per decree. on reels or in fan-fold boxes. Each reel fan-fold box: 3 and each box is marked with labels mm IRED: 2000 pcs 7.2 Order designation which contain the following 5 information: mm IRED: 1000 pcs The type designation of the device is – Tfk extended by the code shown above. This results in the increments for the – Type ordering quantities: Example: TSIP 5200 AS12 – Group (reel packing) or – Tape code (see figure 7.1.) 3 mm: Increments of 2000 pcs TSIP 5200 AS12Z – Production code 5 mm: Increments of 1000 pcs (fan-fold packing) – Quantity BPW 85 AS12 (reel 7.1.2.Missing components packing)

51 TELEFUNKEN Semiconductors

7.2.1 Tape dimensions for ∅ 3 mm standard packages available package variations: 1 2, 1 2Z, 2 1

AS BT "1° "2°

4.5 3.5 0.5 0.1

12 1212 16.5 15.5 4.2 9.5 3.8 8.5 12.3 11.7 19.0 17.5

4.51 94 8171 5.08 3.11

0.9 max 5.78 7.05 12.9 4.38 2.54 5.65 12.5

Figure 7.2 Tape dimensions ∅ 3mm devices

52 TELEFUNKEN Semiconductors

7.2.2 Tape dimensions for ∅ 5 mm standard packages available package variations: 1 2, 1 2Z, 2 1

AS BT CS "1° "2°

4.5 3.5 0.5 0.1

12 1212 22.5 16.5 21.5 15.5 4.2 9.5 3.8 8.5 12.3 11.7 19.0 17.5

4.51 3.11 94 8172 5.08

0.9 max 5.78 7.05 12.9 4.38 2.54 5.65 12.5

Figure 7.3 Tape dimensions ∅ 5 mm devices

53 TELEFUNKEN Semiconductors

7.2.3 Reel package, dimensions in mm

355 52 max.

48 Identification Label : 45 94 8641 Tfk / Type / Group / Tape Code / Production Code / Quantity

Figure 7.4 Dimensions of the reel

54 TELEFUNKEN Semiconductors

Diodes: Anode before Cathode Phototransistors: Emitter before Collector Code 21 Adhesive Tape

Identification Label Reel

Diodes: Cathode before Anode Phototransistors: Collector before Emitter Code 12

Kraft Paper

Tape

94 8671

Figure 7.5 Winded devices

55 TELEFUNKEN Semiconductors

7.2.4 Fan-fold packing The tape is folded an a concertina the cathode before the anode anode before cathode (figure 7.7), it arrangement and it is laid in the (figure 7.6), the start of the tape should be taken from the side of the cardboard box. should be taken from the side of the box marked “+”. If the components are required with box marked “–”; for the direction

Tape Feed Direction Diodes: Cathode before Anode Phototransistors: Collector before Emitter

Identification Label: Tape Feed Direction Tfk Diodes: Anode before Cathode Type Phototransistors: Emitter before Collector Group Tape Code Production Code Quantity 94 8667

Figure 7.6 Tape direction

Table 7.1 Inner dimensions

A B C Packages 34 46 12 ∅5 mm 0 5 34 34 16 ∅3 mm AS-Taping 0 0 34 41 16 ∅3 mm other then 0 0 AS-Taping

56 TELEFUNKEN Semiconductors

7.3 Taping of SMT-devices TEMIC TELEFUNKEN accordance with is a plastic strip with impressed microelectronic IREDs and detectors DIN IEC 40 (CO) 564) for automatic component cavities, covered by a top in SMD packages are available in an component insertion. The blister tape tape. antistatic 8 mm blister tape (in

Adhesive Tape

Blister Tape

Component Cavity 94 8670

Figure 7.7 Blister tape

57 TELEFUNKEN Semiconductors

De - reeling Direction 1.5 max

3.2 max 15_ max

2.7 max 5.75 5.25 3.3 max

3.6 8.3 3.4 7.7

technical drawings according to DIN 1.85 specifications 1.65

1.6 2.05 0.4 max 1.4 1.95 4.1 3.9 94 8157 4.1 3.9

Figure 7.8 Tape dimensions in mm for SOT 23. The mounting side of the components is oriented to the bottom side in the tape.

3.5 2.2 3.1 2.0

5.75 4.0 5.25 3.6 8.3 3.6 7.7 3.4

1.85 1.65

1.6 4.1 4.1 0.25 1.4 3.9 3.9

2.05 94 8668 1.95

Figure 7.9 Tape dimensions in mm for PLCC2

7.3.1 Number of components Quantity per reel in SOT 23 package: 3000 pcs PLCC2 (Tantal B) package: 1500 pcs (minimum quantities for order)

58 TELEFUNKEN Semiconductors

7.3.2 Missing devices

Maximum of 0.5% of the total number components at the beginning and at missing, provided this gap is followed of components per reel may be the end of the reel. Maximum of three by six consecutive components. missing, exclusively missing consecutive components may be De - reeling Direction 94 8158

v 200 mm 10 ... 20 empty min. 10 empty Positions Positions Top Tape Leader Carrier Leader Carrier Trailer Figure 7.10 Beginning and end of reel

The top tape leader is at least 200 mm may include the carrier tape providing carrier tape trailer with at least 10 and is followed by a carrier tap leader the two are not connected together. empty positions, with the top tape with at least 10 and not more than 20 attached to the carrier tape. empty positions. The top tape leader The last component is followed by a 10.0 9.0

120°

4.5 3.5 13.00 2.5 12.75 1.5

63.5 60.5

Identification Label : Tfk Type Group Tape Code Production Code 94 8665 Quantity 180 178 14.4 max.

Figure 7.11 Dimensions of the reel 7.3.3 Top tape removal force from popping out of the blisters, the The type designation of the device in top tape must be pulled off at an angle SMT 23 package is extended by the The removal force lies between 0.1 N of 180°C with respect to the feed code GS08. and 1.0 N at a removal speed of direction. 5 mm/s. Example: TEMD 2100 GS08 In order to prevent the components 7.3.4 Ordering designation

59 TELEFUNKEN Semiconductors

8. Assembly instructions 8.1 General temperature. possible (one minute maximum). In the case of plastic encapsulated Optoelectronic semiconductor 8.2 Soldering devices, the maximum permissible devices can be mounted in any instructions soldering temperature is governed by position. Connection wires may be the maximum permissible heat that bent provided the bend is not less than Protection against overheating is may be applied to the encapsulant 1.5 mm from the bottom of the case. essential when a device is being rather than by the maximum During bending, no forces must be soldered. It is recommended, permissible junction temperature. transmitted from the pins to the case therefore, that the connection wires (e.g. by spreading the pins). are left as long as possible. The time The maximum soldering iron (or If the device is to be mounted near during which the specified maximum solder bath) temperatures are given in heat generating components, then permissible device junction Tab. 8.1. During soldering, no forces consideration must be given to the temperature is exceeded at the must be transmitted from the pins to resultant increase in ambient soldering process should be as short as the case (e.g. by spreading the pins).

Table 8.1 Maximum Soldering Temperatures

Iron soldering Wave or reflow soldering Iron Distance of Maximum Soldering Distance of Maximum temperature the soldering allowable sol- temperature the soldering allowable sol- position from dering time position from dering time the lower edge see temperature/ the lower edge of the case time profiles of the case Devices in x245_C y1.5 mm 5s 245_C y1.5 mm 5s metal case x245_C y5.0 mm 10 s x350_C y5.0 mm 5s 300_C y5.0 mm 3s Devices in x260_C y2.0 mm 5s 235_C y2.0 mm 8s plastic case x300_C y5.0 mm 3s 260_C y2.0 mm 5s w3 mm Devices in plastic case x300_C y5.0 mm 3s 260_C y2.0 mm 3s <3 mm

Soldering Methods (b) Infrared soldering measuring the temperature of a With infrared (IR) reflow soldering certain component while it is There are several methods in use to transported through the furnace. solder devices on to the substrate. The the heating is contact-free and the following is not given as a complete energy for heating the assembly is The temperatures of small list. derived from direct infrared radiation components, soldered together with and from convection. larger ones, may rise up to 280_C. (a) Soldering in the vapor phase The heating rate in an IR furnace Soldering in saturated vapor is also depends on the absorption known as condensation soldering. coefficients of the material surfaces This soldering process is in use as a and on the ratio of component’s mass batch system (dual vapor system) or to As irradiated surface. as a continuous single vapor system. The temperature of parts in an IR Both systems may also include a furnace, with a mixture of radiation preheating of the assemblies to and convection, cannot be determined prevent high temperature shock and in advance. Temperature other undesired effects. measurement may be performed by 60 TELEFUNKEN Semiconductors

Influencing parameters on the internal parameters are given in figure 8.1. is no SMD classification for this temperature of the component are as process. (c) Wave soldering follows: In wave soldering one or more (e) Laser soldering – Time and power continuously replenished waves of This is an excess heating soldering – Mass of the component molten solder are generated, while the method. The energy absorbed may – Size of the component substrates to be soldered are moved in heat the device to a much higher – Size of the printed circuit board one direction across the crest of the temperature than desired. There is no – Absorption coefficient of the wave. SMD classification for this process at surfaces the moment. – Packing density Temperature/time profiles of the – Wavelength spectrum of the entire process are given in figure 8.2. (f) Resistance soldering radiation source (d) Iron soldering – Ratio of radiated and convected This is a soldering method which uses energy This process is essentially temperature controlled tools uncontrolled. It should not be (thermodes) for making solder joints. Temperature/time profiles of the considered for use in applications There is no SMD classification for entire process and the influencing where reliability is important. There this process at the moment.

Temperature-Time-Profiles

94 8625 300 5 s

260 °C 250 ca. 245°C

215 °C

200 180 °C 10 s °

150 130 °C ca. 40 s Temperature ( C ) Temperature 100

full line : typical 2 K/s dotted line : process limits

50 Lead Temperature

0 50 100 150 200 250

Time ( s ) Figure 8.1 Infrared reflow soldering opto-devices (SMD package)

61 TELEFUNKEN Semiconductors

94 8626 300 5 s Lead Temperature

250 235 °...260 °C second wave full line : typical dotted line : process limits first wave 200

° ca. 200 K/s ca. 2 K/s 150

forced cooling Temperature ( C ) Temperature ° ° 100 ...130 C ca. 5 K/s 100

2 K/s 50

0 0 50 100 150 200 250

Time ( s )

Figure 8.2 Wave soldering double wave opto-devices

8.3 Heat removal to the case or header by conduction expressed in terms of an RthCA value, rather than convection. A measure of i.e., the external or case ambient To keep the thermal equilibrium, the the effectiveness of heat conduction is thermal resistance. The total thermal heat generated in the semiconductor the inner thermal resistance or resistance, junction ambient is junction(s) must be removed and the thermal resistance junction case, consequently: junction returned to ambient RthJC, the value of which is governed temperature. by the construction of the device. RthJA = RthJC + RthCA In the case of low power devices, the natural heat conductive path between Any heat transfer from the case to the The total maximum power the case and surrounding air is usually surrounding air involves radiation dissipation, Ptot max of a adequate for this purpose. The heat convection and conduction, the semiconductor device can be generated in the junction is conveyed effectiveness of transfer being expressed as follows: Tjmax – Tamb Tjmax – Tamb Ptot max = = RthJA RthJC + RthCA where: junction ambient, is a heat specified for the components. dissipator or sink is used, then R Tjmax the maximum allowable thCA junction temperature The following depends diagram shows how the different on the thermal contact between case T the highest ambient amb installation and heat temperature likely to be conditions effect the thermal sink, heat propagation conditions in reached under the most resistance the sink and unfavorable conditions the rate at which heat is transferred to R the thermal resistance, thJC RthCA the thermal resistance, case the junction case ambient. RthCA surrounding air. RthJA the thermal resistance, depends on cooling conditions. If 62 TELEFUNKEN Semiconductors

Cu Commercially available grades (industrial use) shall be used. 100 b 2.5 Warning: The component 1, 1.2-trichlorofluoroethane is hazardous to the environment. Therefore this solvent must not be

thJA 90 R ( % ) c 2.54 used where the solvent specified in 2 or 3 is adequate. 100 mm2 2) 2-propanol (isopropyl alcohol). Commercially available grades 80 (industrial use) should be used. Cathode 515 3) Demineralized or distilled water 94 8161 Length ( mm l having a resistivity of not less than Figure 8.3 Thermal resistance 500 mW corresponding to a junction/ambient conductivity of 2 mS/m. vs. lead length 94 8164 Caution: The use of tetrachlor, c. with PC board with heatsink acetone, trichloroetylene 94 8162 or similar is NOT 8.4 Cleaning ALLOWED! l Soldered assemblies are washable 3 with the following solvents: 8.5 Warning 1) A mixture of 1, Exceeding any one of the ratings w100 1.2-trichlorotrifluoroethane, 70$5% (soldering, cleaning or short time by weight and 2-propanol (isopropyl exceeding the railings) could result in alcohol), 30$5% by weight. irreversible changes in the ratings.

0.14 mm2 Cu isolated a. with wires

2.5

2.54

94 8163 b. with PC board without heatsink