LT3464 Micropower Boost Converter with Schottky and Output Disconnect in ThinSOT™

FEATURES DESCRIPTIO U ■ Tiny Solution Size The LT®3464 is a micropower step-up DC/DC converter ■ Low Quiescent Current with integrated Schottky and output disconnect • 25µA in Active Mode packaged in an 8-lead low profile (1mm) SOT-23. The • 0.5µA in Shutdown Mode small package size, high level of integration, and the use ■ Internal 115mA, 36V of tiny SMT components yield a solution size of less than ■ Integrated 40mm2. The LT3464 has a typical current limit of 115mA ■ Integrated PNP Output Disconnect with as well as fast switching speed to allow the use of a chip Short-Circuit Protection and small ceramic . The internal PNP ■ Internal Reference Override Pin disconnects the output load from the input during shut- ■ 16V at 8mA from 3.6V Input down, and also provides output short-circuit protection. ■ 12V at 20mA from 5V Input An auxiliary reference input allows the user to override the ■ Input Range: 2.3V to 10V internal 1.25V feedback reference with any lower value, ■ High Output Voltage: Up to 34V allowing full control of the output voltage during opera- ■ Low Profile (1mm) SOT-23 Package tion. This device features a low 25 µA quiescent current,

µ U which is further reduced to less than 0.5 A in shutdown. APPLICATIO S A current limited fixed off-time control scheme conserves operating current, resulting in high efficiency over a broad ■ OEL Panel Bias range of operating current. The rugged 36V switch and ■ LCD Bias output disconnect circuitry allow outputs up to 34V to be ■ Handheld Computers easily generated in a simple boost topology. ■ Battery Backup , LTC and LT are registered trademarks of Linear Technology Corporation. ■ Digital Cameras ThinSOT is a trademark of Linear Technolgy Corporation ■ Cellular Phones

TYPICAL APPLICATIO U

Efficiency 22µH VIN 90 2.3V TO 10V VIN = 8.4V 80 V IN SW VIN = 4.2V V OUT OUT 16V 70 CTRL 0.22µF 1µF LT3464 CAP 60 SHDN 0.33µF 3.48M EFFICIENCY (%) 50 FB

GND 294k 40

3464 TA01a 30 0.010.1 1 10 100 LOAD CURRENT (mA)

3464 TA01b 3464f 1

LT3464

WW U W W

ABSOLUTE AXI U RATI GS PACKAGE/ORDER IUU FOR ATIO (Note 1) ORDER PART VIN, SHDN, CTRL Voltage ...... 10V TOP VIEW NUMBER OUT, CAP Voltage ...... 36V CTRL 1 8 SHDN SW Voltage ...... 36V FB 2 7 VIN LT3464ETS8 FB Voltage ...... 6V OUT 3 6 SW ° GND 4 5 CAP Maximum Junction Temperature ...... 125 C TS8 PART MARKING ° ° TS8 PACKAGE Operating Temperature Range (Note 2) .. –40 C to 85 C 8-LEAD PLASTIC SOT-23 ° ° ° θ ° θ ° LTG2 Storage Temperature Range ...... –65 C to 150 C TJMAX = 125 C, JA = 140 C/W, JC = 85 C/W Lead Temperature (Soldering, 10 sec)...... 300°C Consult LTC Marketing for parts specified with wider operating temperature ranges.

ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3.6V, unless otherwise noted. (Note 2)

PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Input Voltage 2.0 2.3 V Quiescent Current Not Switching 25 36 µA µ VSHDN = 0.2V 0.01 0.5 A ● FB Comparator Trip Voltage VFB Falling, VCTRL = 3.6V 1.215 1.250 1.275 V FB Comparator Hysteresis 10 mV

FB Pin Bias Current VFB = 1.25V, VCTRL = 3.6V ● 330nA

FB Voltage Line Regulation 2.3V < VIN < 10V 0.05 0.1 %/V

Switch Off Time VCAP-VIN = 5V 250 ns µ VCAP-VIN = 0V 1.0 s µ Switch Leakage Current VSW = 36V 0.02 1 A

Switch VCESAT ISW = 80mA 190 300 mV Switch Current Limit 85 115 140 mA

Schottky Forward Voltage ISCHOTTKY = 110mA 600 750 mV

Schottky Reverse Leakage VCAP-SW = 36V 1 10 µA

PNP Disconnect VCAP-OUT IOUT = 200µA 100 mV IOUT = 10mA 190 mV

PNP Disconnect Q Current IOUT = 0, VCAP = 36V (Note 3) 1.5 5 µA µ PNP Disconnect Leakage SHDN = 0.2, VCAP = 10V, VOUT = 0V 0.1 5 A

PNP Disconnect Current Limit VCAP = 10V, VOUT = 0V 25 45 75 mA µ SHDN Pin Current VSHDN = 3.6V 5 10 A SHDN Input Voltage High 2.3 V SHDN Input Voltage Low 0.2 V ● CTRL Pin Bias Current VCTRL = 0.5V, VFB = 1V 680nA

CTRL to FB Offset VCTRL = 0.5V (Note 4) 2 7 mV Note 1: Absolute Maximum Ratings are those values beyond which the life Note 3: Current consumed by Disconnect PNP when there is no load on of a device may be impaired. the OUT pin. Note 2: The LT3464E is guaranteed to meet performance specifications Note 4: This figure is computed according to ((VFB falling + VFB rising)/2) from 0°C to 70°C. Specifications over the –40°C to 85°C operating –VCONTROL. temperature range are assured by design, characterization and correlation with statistical process controls.

3464f 2 LT3464

TYPICAL PERFOR A UW CE CHARACTERISTICS

Switch Saturation Voltage ISW = 80mA Switch Current Limit Switch Off-Time, VCAP – VIN = 5V 220 140 400

350 200 120 300 100 180 250 80 160 200 60 150 140 40 SWITCH VOLTAGE (mV) SWITCH CURRENT (mA) SWITCH OFF-TIME (ns) 100 120 20 50

100 0 0 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C)

3464 G01 3464 G02 3464 G03

Minimum Switch On-Time Switch Off-Time, VCAP – VIN = 0V Output Disconnect Voltage Drop 100 1.3 300 90 1.2 250 80 1.1 IOUT = 10mA

70 µ s) 200 60 1.0 50 0.9 150 IOUT = 200µA 40 0.8 100

30 VOLTAGE DROP (mV) SWITCH ON-TIME (ns) SWITCH OFF-TIME ( 0.7 20 50 10 0.6 0 0.5 0 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C)

3464 G04 3464 G05 3464 G06

Output Disconnect Quiescent Current Output Disconnect Current Limit Output Disconnect Voltage Drop 2.0 60 300 1.8 50 250 1.6

µ A) 1.4 40 200 1.2 1.0 30 150 0.8 20 100

0.6 VOLTAGE DROP (mV) CURRENT LIMIT (mA)

QUIESCENT CURRENT ( 0.4 10 50 0.2 0 0 0 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 0 10 20 30 TEMPERATURE (°C) TEMPERATURE (°C) COLLECTOR CURRENT (mA)

3464 G07 3464 G08 3464 G09

3464f 3 LT3464

TYPICAL PERFOR A CEUW CHARACTERISTICS

Schottky Forward Drop at ID = 110mA Schottky Forward Voltage Schottky Reverse Leakage 800 250 20 VCAP – SW = 36V 750 700 200 16

650 µ A) 600 150 12 550 500 100 8 450 VOLTAGE DROP (mV) LEAKAGE CURRENT ( 400 SCHOTTKY CURRENT (mA) 50 4 350 300 0 0 –50 –25 0 25 50 75 100 200 300 400 500 600 700 800 –50 –25 0 25 50 75 100 ° TEMPERATURE (°C) FORWARD VOLTAGE (mV) TEMPERATURE ( C)

3464 G10 3464 G11 3464 G20

Shutdown Pin Current Quiescent Current in Quiescent Current VSHDN = 3.6V Shutdown Mode 30 12 16 28 14 10 26 µ A) 12 µ A) 24 8 22 10 20 6 8 18 6 4 16 4 QUIESCENT CURRENT (nA) QUIESCENT CURRENT ( 14 SHUTDOWN PIN CURRENT ( 2 12 2 10 0 0 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C)

3464 G12 3464 G13 3464 G14

Quiescent Current in Regulation with No Load SHDN Pin Threshold Voltage FB Pin Voltage 70 3.0 1.30 2.8 60 2.6 1.28 µ A) 50 2.4 1.26 40 2.2 2.0 30 1.8 1.24

20 1.6 FB PIN VOLTAGE (V) SHDN PIN VOLTAGE (V) QUIESCENT CURRENT ( 1.4 1.22 10 VIN = 5V 1.2 FRONT PAGE SCHEMATIC 0 1.0 1.20 6 8101214 16 18 20 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 ° TEMPERATURE (°C) VOUT (V) TEMPERATURE ( C) 3464 G16 3464 G18 3464 G15

3464f 4 LT3464

TYPICAL PERFOR A CEUW CHARACTERISTICS

FB Pin Voltage vs FB and CTRL Pin CTRL Pin Voltage Bias Currents FB Pin Hysteresis 1.50 8 12

7 1.25 CTRL PIN 10 6 1.00 8 5

0.75 4 6 FEEDBACK PIN 3

0.50 HYSTERESIS (mV) 4 BIAS CURRENT (nA) FB PIN VOLTAGE (V) 2 0.25 2 1

0 0 0 0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100

CONTROL PIN VOLTAGE (V) TEMPERATURE (°C) TEMPERATURE (°C)

3464 G17 3464 G18 3464 G19 UU

PI U FU CTIO S CTRL (Pin 1): Internal Reference Override Pin. This allows GND (Pin 4): Ground. Tie this pin directly to the ground the FB voltage to be externally set between 0V and 1.25V. plane. Tie this pin to above 1.5V (V IN for example) to use the CAP (Pin 5): PNP Emitter and Schottky Cathode. This pin internal 1.25V reference. connects to the output , and optionally to the  external phase-lead capacitor. =+R2 VVOUT CTRL1 SW (Pin 6): Switch Pin and Schottky Anode. This is the R1 collector of the internal NPN power switch. Minimize the metal trace area connected to the pin to minimize EMI. when VCTRL is less than 1.25V (see Figure 4) FB (Pin 2): Feedback Pin. The LT3464 regulates its feed- VIN (Pin 7): Input Supply Pin: Bypass this pin with a back pin to 1.25V if the internal reference is used or to capacitor located as close to the device as possible. VCTRL if the CTRL pin is between 0V and 1.25V. Connect SHDN (Pin 8): Shutdown Pin. This pin is used to put the the feedback divider tap to this pin. Set the output device in shutdown mode. Tie the pin low to shut down the voltage by selecting R1 and R2 (see Figure 4). LT3464. Tie high for normal operation See the electrical specifications for the required voltages. V  RR21=OUT – 1 VREF  OUT (Pin 3): PNP Collector. This is the output of the Output Disconnect circuit. Bypass this pin with at least a 0.1µF capacitor connected to the CAP pin or to ground.

3464f 5 LT3464

BLOCK DIAGRA W

VIN SW CAP OUT 7 6 5 3

DELAY CPL

FB 2 S Q

R Q + CTRL 1 – OUT ANTI – SAT + 1.25V OUT 12mV

– 0.1Ω

SHDN 8 VREF

4 3464 BD GND

OPERATIOU The LT3464 uses a constant off-time control scheme in point where the current limit is reached, at which point the conjunction with Burst Mode® operation to provide high switch turns off for a fixed amount of time. While the efficiency over a wide range of output current. Operation switch is off the inductor is delivering current to the load. can best be understood by studying the Block Diagram. When the off time expires, the switch turns on again until When the FB pin voltage is lower than the 1.25V reference, the current limit is reached, and the cycle repeats. the hysteretic comparator enables the power section, This chip includes an internal power Schottky diode and a causing the chip to start switching, thus charging the PNP for output disconnect. The PNP transistor output capacitor. When the output voltage increases disconnects the load from the input during shutdown. The enough to overcome the hysteresis, the feedback com- PNP control circuitry is designed to keep the PNP out of parator shuts off the power section leaving only low power saturation across a wide range of current, to keep quies- circuitry running until the output voltage falls again. This cent current to a minimum and to provide current limiting cycle repeats, keeping the output voltage within a small to protect the chip during short-circuit conditions. window. The switching action is as follows: The switch turns on, and current through it starts to ramp up until the

Burst Mode is a registered a trademark of Linear Technolgy Corporation. 3464f 6

LT3464 W

SWITCHIUW G TI E WAVEFOR S

Operating Waveforms Start up Waveforms

IL IL 0.1A/DIV 0.1A/DIV

VOUT 50mV/DIV VOUT 10V/DIV

µ 50µs/DIV VIN = 5V 5 s/DIV VOUT = 20V ILOAD = 1mA L = 22µH

Shutdown Waveforms

SHDN

5V/DIV

VIN = 5V CAP PIN VOLTAGE

GND VOUT: THE OUTPUT DISCONNECT ALLOWS VOUT TO BE AT GROUND DURING SHUTDOWN 1ms/DIV

3464f 7

LT3464

U U

APPLICATIO S I FOR ATIOWU Choosing an Inductor in discontinuous mode. If the left hand side of inequality 1 The low current limit and fast switching of the LT3464 evaluates to less than OFFt , then use Equation 3 to calculate allow the use of very small surface mount . The maximum output current. Otherwise, use Equation 2. minimum inductor size that may be used in a given This inequality is true when the LT3464 is operating in application depends on required efficiency and output discontinuous mode. current. Some inductors that work with the LT3464 are listed in Table 1, although there are many other manufac- LILIM < tOFF (INEQUALITY 1) turers and devices that can be used. Consult each manu- (–VVV+ ) facturer for more detailed information and for their entire OUT IN F selection of related parts. Many different sizes and shapes Use this equation to calculate the maximum output current are available. when the LT3464 is operating in continuous mode. Table 1. Recommended Inductors PART NUMBER µH DCR CURRENT MANUFACTURER IOUT() CM = (Ω) (mA) + (2LILIM t OFF ( V IN – V OUT – V F ))( V IN – V CESAT ) (2) LQH32CN680K53 68 2.2 130 Murata + LQH32CN470K53 47 1.3 170 814-237-1431 2LV(–OUT V CESAT V F ) LQH32CN220K53 22 0.71 250 www.murata.com ELJPC220KF 22 4.0 160 Panasonic Use this equation to calculate the maximum output current ELJPA470KF 47 2.25 135 714-373-7334 when the LT3464 is operating in discontinuous mode. www.panasonic.com CMD4D11-47 47 2.2 180 Sumida I = 847-956-0666 OUT() DCM www.Sumida.com 2 LILIM(– V IN V CESAT ) LB2016-220 22 1.0 105 Taiyo Yuden (3) LEM2520-220 22 5.5 125 408-573-4150 2(LILIM+++ V IN t OFF – t OFF V CESAT )(– V IN V OUT V F ) LEM2520-330 33 7.1 110 www.t-yuden.com LEMC2520-220 22 2.7 160 Where VF is the Schottky forward voltage,LIM I is the switch LEMC2520-330 33 4.8 120 current limit, t is the switch off time, and V is the LEMF2520-220 22 1.2 105 OFF CESAT LEMC3225-680 68 3.3 120 switch saturation voltage. See the Electrical Specifications. LEMC3225-101 100 4.3 100 Figures 1 through 3 show the worst-case maximum output current as given by Equations 2 and 3 using 20% inductor The following set of formulas can be used to calculate derating and worst-case LT3464 specifications. Also note maximum output current given V IN, VOUT and L values. that for some applications the maximum output current is Inequality 1 is used to determine if the LT3464 is operating limited to 25mA by the output disconnect circuitry.

25 25 17.5

15.0 L = 47µH 20 µ 20 L = 47 H L = 47µH 12.5 L = 22µH µ 15 L = 22 H 15 µ 10.0 L = 22 H (mA) (mA)

(mA) µ L = 10 H OUT µ I µ OUT L = 10 H

L = 10 H I 10

OUT 7.5 10 I

5.0 5 5 2.5 µ L = 4.7µH L = 4.7µH L = 4.7 H 0 0 0 10 15 2025 30 35 15 2025 30 35 10 15 20 25 30 35 VOUT (V) VOUT (V) 3464 F02 3464 F03 VOUT (V) 3464 F01 Figure 1. Maximum Output Current Figure 2. Maximum Output Current Figure 3. Maximum Output Current V = 8.4V VIN = 3.6V VIN = 5V IN 3464f 8

LT3464 UU

APPLICATIO S I FOR ATIOWU Capacitor Selection user to select between using the built-in reference, and supplying an external reference voltage. The voltage at the The small size and low ESR of ceramic capacitors makes CTRL pin can be adjusted while the chip is operating to them suitable for LT3464 applications. X5R and X7R types alter the output voltage of the LT3464 for purposes such are recommended because they retain their capacitance as display dimming or contrast adjustment. To use the over wider voltage and temperature ranges than other internal 1.25V reference, the CTRL pin must be held higher types such as Y5V or Z5U. A 1 µF input capacitor and a than 1.5V, which can be done by tying it to V . When the 0.22µF to 0.47µF output capacitor are sufficient for most IN CTRL pin is held between 0V and 1.2V the LT3464 will LT3464 applications. Always use a capacitor with a suffi- regulate the output such that the FB pin voltage is equal to cient voltage rating. Table 2 shows a list of several capaci- the CTRL pin voltage. tor manufacturers. Consult the manufacturers for more detailed information and for their entire selection of related To set the output voltage, select the values of R1 and R2 parts. according to the following equation (see Figure 4). Table 2. Recommended Ceramic Capacitor Manufacturers V  MANUFACTURER PHONE URL RR21=OUT – 1 Taiyo Yuden 408-573-4150 www.t-yuden.com VREF  AVX 843-448-9411 www.avxcorp.com Where V =1.25V if the internal reference is used, or Murata 814-237-1431 www.murata.com REF V = V if V is between 0V and 1.2V. Kemet 408-986-0424 www.kemet.com REF CTRL CTRL Choosing a Feedback Node Output Voltage Ripple The top of the feedback divider may be connected to the Using low ESR capacitors will help minimize the output OUT pin or to the CAP pin (see Figure 4). Regulating the ripple voltage, but proper selection of the inductor and the OUT pin eliminates the output offset resulting from the output capacitor also plays a big role. The LT3464 pro- voltage drop across the output disconnect. However, in vides energy to the load in bursts by ramping up the the case of a short-circuit fault at the OUT pin, the LT3464 inductor current, then delivering that current to the load. will switch continuously because the FB pin is low. While If too large an inductor value or too small a capacitor value operating in this open-loop condition, the rising voltage at is used, the output ripple voltage will increase because the the CAP pin is limited only by the current limit of the output capacitor will be slightly overcharged each burst cycle. To disconnect. Given worst-case parameters this voltage reduce this effect, a larger output capacitor may be used. may reach 25V. When the short-circuit is removed, the The LT3464 also includes an on-chip phase-lead capacitor OUT pin will bounce up to the voltage on the CAP pin, between the CAP pin and the FB pin to greatly reduce potentially exceeding the set output voltage until the ripple; however, certain applications can benefit from capacitor voltages fall back into regulation. While this is additional capacitance in parallel with the integrated ca- harmless to the LT3464, this should be considered in the pacitor, which may be added externally between the CAP context of the external circuitry if short-circuit events are and FB pins. Typical effective values range from 4.7pF to expected. 20pF. Since the FB pin sits at a low voltage, be sure the Regulating the CAP pin ensures that the voltage on the chosen capacitor has a sufficient voltage rating. OUT pin never exceeds the set output voltage after a short- circuit event. However, this setup does not compensate Setting Output Voltage and the for the voltage drop across the output disconnect, result- Auxiliary Reference Input ing in an output voltage that is slightly lower than the The LT3464 is equipped with both an internal 1.25V voltage set by the resistor divider. The next section dis- reference and an auxiliary reference input. This allows the cusses how to compensate for this drop. 3464f 9

LT3464 UU

APPLICATIO S I FOR ATIOWU

300

7 6 7 6 250

VIN SW VIN SW 3 3 200 OUT VOUT OUT VOUT 1 1 CTRL CTRL (SAT) 5 5 150 LT3464 CAP R2 LT3464 CAP CAP-OUT

8 8 V SHDN SHDN R2 100 2 2 FB FB 50 GND R1 GND R1 4 4 0 0 5101520 3025 3464 F01 COLLECTOR CURRENT (mA)

3464 F02

Figure 4. Feedback Connection Using the CAP Pin and the OUT Pin Figure 5: Output Disconnect Voltage Drop (VDROP) vs Current

Output Disconnect Considerations indefinite short, but care must be taken to avoid exceeding the maximum junction temperature. The LT3464 is equipped with an output disconnect that isolates the load from the input during shutdown. See the Inrush Current Operation section for a functional diagram. The output disconnect uses a pass PNP coupled with circuitry that When VIN is stepped from ground to operating voltage varies the base current such that the transistor is consis- while the output capacitor is discharged, an inrush current tently at the edge of saturation, thus yielding the best will flow through the inductor and integrated Schottky diode into the output capacitor. Conditions that increase compromise between VCE(SAT) and low quiescent current. To remain stable, this circuit requires a bypass capacitor inrush current include a larger more abrupt voltage step at connected between the OUT pin and the CAP pin or VIN, a larger output capacitor tied to the CAP pin, and an between the OUT pin and ground. A ceramic capacitor with inductor with a low saturation current. µ a value of at least 0.1 F is a good choice. While the internal diode is designed to handle such events, the inrush current should not be allowed to exceed 1 amp. The PNP VCE(SAT) varies with load current as shown in For circuits that use output capacitor values within the Figure 5. This voltage drop (VDROP) can be accounted for when using the CAP pin as the feedback node by setting recommended range and have input voltages of less than the output voltage according to the following formula: 5V, inrush current remains low, posing no hazard to the device. In cases where there are large steps at V IN   (more than 5V) and/or a large capacitor is used at the CAP VVOUT+ DROP RR21= –1 pin, inrush current should be measured to ensure safe  V  REF operation. In addition, the disconnect circuit has a built in current limit of 25mA (minimum) to protect the chip during short- circuit. This feature allows the LT3464 to tolerate an

3464f 10

LT3464 UU

APPLICATIO S I FOR ATIOWU Board Layout Considerations pin has sharp rising and falling edges. Minimize the length As with all switching regulators, careful attention must be and area of all traces connected to the SW pin and always paid to the PCB board layout and component placement. use a ground plane under the switching regulator to To maximize efficiency, switch rise and fall times are made minimize interplane coupling. In addition, the ground as short as possible. To prevent electromagnetic interfer- connection for the feedback resistor R1 should be tied ence (EMI) problems, proper layout of the high frequency directly to the GND pin and not shared with any other switching path is essential. The voltage signal of the SW component, ensuring a clean, noise-free connection. Rec- ommended component placement is shown in Figure 6.

GND

VIN

GND

VOUT

VIAS TO GROUND PLANE VIA TO CONTROL VIA TO SHDN

3464 F07

Figure 6. Recommended Layout

3464f 11 LT3464

TYPICAL APPLICATIO SU

15V Output Converter with Output Disconnect L1 22µH VIN 2.3V TO 10V 7 6

VIN SW 3 V OUT OUT 15V 1 C3 C1 CTRL 0.22µF 1µF 5 LT3464 CAP VIN (V) IOUT (mA) 8 C2 R2 SHDN µ 0.22 F 3.32M 3.6 7.0 2 FB 5.0 10.0 GND R1 301k 4 8.4 19.0 3464 TA02 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN EMK107 BJ224MA-T C3: TAIYO YUDEN EMK107 BJ224MA-T L1: MURATA LQH32CN220K

34V Output Converter with Output Disconnect L1 47µH VIN 2.3V TO 10V 7 6

VIN SW 3 V OUT OUT 34V 1 C3 C1 CTRL 0.22µF 1µF 5 LT3464 CAP VIN (V) IOUT (mA) 8 C2 R2 SHDN µ 0.33 F 2.61M 3.6 3.5 2 FB 5.0 4.5 GND R1 100k 4 8.4 7.5 3464 TA03 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN UMK212 BJ224MG-T L1: MURATA LQH32CN470K

20V Output Converter with Output Disconnect Using an 0805 Inductor and 0603 Capacitors L1 10µH VIN 2.3V TO 10V 7 6

VIN SW 3 OUT VOUT 20V 1 C3 C1 CTRL 0.1µF 1µF 5 LT3464 CAP VIN (V) IOUT (mA) 8 C2 R2 SHDN µ 0.1 F 4.53M 3.6 3.0 2 FB 5.0 4.0 GND R1 301k 4 8.4 6.0 3464 TA04 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN TMK107 BJ104MA-T C3: TAIYO YUDEN TMK107 BJ104MA-T L1: TAIYO YUDEN LB 2012T100MR

3464f 12 LT3464

TYPICAL APPLICATIO SU

20V Output Converter with Output Disconnect

L1 47µH VIN 2.3V TO 10V 7 6

VIN SW 3 V OUT OUT 20V 1 C3 C1 CTRL µ 0.22 F VIN (V) IOUT (mA) 1µF 5 LT3464 CAP 3.6 6.0 8 C2 R2 SHDN µ 0.33 F 4.53M 2 5.0 9.0 FB GND R1 8.4 16.5 301k 4 3464 TA05 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN UMK212 BJ224MG L1: MURATA LQH32CN470K

20V Output Converter with Soft Start

L1 22µH VIN 2.3V TO 10V 7 6 OFF ON VIN SW 3 OUT VOUT 20V 8 C3 C4 SHDN 0.22µF V (V) I (mA) 1µF 5 IN OUT R1 LT3464 CAP 300k 3.6 5.0 1 C2 R2 CTRL µ 0.33 F 4.53M 2 5.0 6.5 FB C4 0.1µF GND R1 8.4 11.0 301k 4 3464 TA06 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN EMK107 BJ224MA-T L1: MURATA LQH32CN220K

3464f 13 LT3464

TYPICAL APPLICATIO SU

8V Output Converter with Output Disconnect

L1 22µH VIN 2.3V TO 7V 7 6

VIN SW 3 OUT VOUT 8V 8 C3 C4 SHDN 0.47µF 1µF 5 LT3464 CAP VIN (V) IOUT (mA) 1 R2 CTRL C2 C4 3.6 13.5 1.62M 2 2.2µF 20pF FB 5.0 20 GND R1 301k 4 3464 TA07 C1: TAIYO YUDEN CE LMK107 BJ105MA-T C2: TAIYO YUDEN CE LMK212 BJ225MG-T C3: TAIYO YUDEN CE LMK107 BJ474MA-T L1: MURATA LQH32CN220K

±20V Dual Output Converter with Output Disconnect

–VOUT I = 2.5mA AT V = 3.6V –20V OUT IN L1 C5 D1 D2 C4 µ µ 47 H 0.33 F 0.33µF VIN 2.3V TO 10V 7 6

VIN SW 3 V OUT I = 2.5mA AT V = 3.6V OUT 20V OUT IN 1 C3 C1 CTRL 0.22µF 1µF 5 LT3464 CAP 8 C2 R2 SHDN µ 0.33 F 4.53M 2 FB GND R1 301k 4 3464 TA08 C1: TAIYO YUDEN LMK107 BJ105MA-T C2, C4, C5: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN UMK212 BJ224MG-T L1: MURATA LQH32CN470K D1, D2: CENTRAL CMDSH-3

3464f 14 LT3464

PACKAGE DESCRIPTIO U

TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637)

0.52 0.65 2.90 BSC MAX REF (NOTE 4)

1.22 REF

2.80 BSC 1.50 – 1.75 3.85 MAX 2.62 REF 1.4 MIN (NOTE 4)

PIN ONE ID

RECOMMENDED SOLDER PAD LAYOUT 0.22 – 0.36 0.65 BSC PER IPC 8 PLCS (NOTE 3)

0.80 – 0.90

0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’

0.30 – 0.50 REF 0.09 – 0.20 1.95 BSC (NOTE 3) TS8 TSOT-23 0802 NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193

3464f

Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LT3464

TYPICAL APPLICATIO SU

20V Output Converter with Variable Output Voltage and Shutdown

L1 22µH VIN 2.3V TO 10V C1 1µF 7 6 VIN SW 3 V OUT OUT 20V 1 C3 DAC CTRL 0.22µF V (V) I (mA) 5 IN OUT LT3464 CAP 8 C2 R2 3.6 5.0 µC SHDN µ 0.33 F 4.53M 2 FB 5.0 6.5 GND R1 8.4 11.0 301k 4 3464 TA09

C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN GMK212 BJ224MG-T L1: MURATA LQH32CN220K

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LT1613 550mA (ISW), 1.4MHz, High Efficiency VIN = 0.9V to 10V, VOUT(MAX) = 34V, IQ = 3mA, ISD = <1µA, Step-Up DC/DC Converter ThinSOT Package µ µ LT1615/ 300mA/80mA (ISW), Constant Off-Time, VIN = 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20 A, ISD = <1 A, LT1615-1 High Efficiency Step-Up DC/DC Converter ThinSOT Package

LT1618 Constant Current, Constant Voltage, 1.4MHz, VIN = 1.6V to 18V, VOUT(MAX) = 34V, IQ = 1.8mA, ISD = <1µA, High Efficiency Boost Regulator MS Package, Up to 6 White LEDs

LT1932 Constant Current, 1.2MHz, High Efficiency VIN = 1V to 10V, VOUT(MAX) = 34V, IQ = 1.2mA, ISD = <1µA, White LED Boost Regulator ThinSOT Package, Up to 8 White LEDs µ LT1937 Constant Current, 1.2MHz, High Efficiency VIN = 2.5V to 10V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD = <1 A, White LED Boost Regulator SC-70, ThinSOT Packages, Up to 4 White LEDs

LT1944 Dual Output 350mA (ISW), Constant Off-Time, VIN = 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD = <1µA, High Efficiency Step-Up DC/DC Converter MS Package µ µ LT1944-1 Dual Output 150mA (ISW), Constant Off-Time, VIN = 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20 A, ISD = <1 A, High Efficiency Step-Up DC/DC Converter MS Package ± ± µ µ LT1945 Dual Output, 350mA (ISW), Constant Off-Time, VIN = 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20 A, ISD = <1 A, High Efficiency Step-Up DC/DC Converter MS Package µ LTC3200/ Low Noise, 2MHz, Regulated VIN = 2.7V to 4.5V, IQ = 8mA, ISD = <1 A, LTC3200-5 White LED Driver MS, ThinSOT Packages, Up to 6 White LEDs

LTC3201 Low Noise, 1.7MHz, Regulated Charge Pump VIN = 2.7V to 4.5V, IQ = 6.5mA, ISD = <1µA, White LED Driver MS Package, Up to 6 White LEDs

LTC3202 Low Noise, 1.5MHz, Regulated Charge Pump VIN = 2.7V to 4.5V, IQ = 5mA, ISD = <1µA, White LED Driver MS Package, Up to 8 White LEDs

LTC3400/ 600mA (ISW), 1.2MHz, Synchronous VIN = 0.85V to 5V, VOUT(MAX) = 5V, IQ = 19µA/300µA, ISD = <1µA, LTC3400B Step-Up DC/DC Converter ThinSOT Package

LTC3401 1A (ISW), 3MHz, Synchronous VIN = 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38µA, ISD = <1µA, Step-Up DC/DC Converter MS Package

LTC3402 2A (ISW), 3MHz, Synchronous VIN = 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38µA, ISD = <1µA, Step-Up DC/DC Converter MS Package 3464f Linear Technology Corporation LT/TP 0204 1K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 16 ● ●  (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 2003