N-Channel MOSFET Gate Driver

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LTC4441/LTC4441-1 N-Channel MOSFET Gate Driver Features Description n 6A Peak Output Current The LTC®4441/LTC4441-1 is an N-channel MOSFET gate n Wide VIN Supply Range: 5V to 25V driver that can supply up to 6A of peak output current. n Adjustable Gate Drive Voltage: 5V to 8V The chip is designed to operate with a supply voltage of n Logic Input Can Be Driven Below Ground up to 25V and has an adjustable linear regulator for the n 30ns Propagation Delay gate drive. The gate drive voltage can be programmed n Supply Independent CMOS/TTL Input Thresholds between 5V and 8V. n Undervoltage Lockout The LTC4441/LTC4441-1 features a logic threshold driver n Low Shutdown Current: <12µA input. This input can be driven below ground or above the n Overtemperature Protection driver supply. A dual function control input is provided to n Adjustable Blanking Time for MOSFET’s disable the driver or to force the chip into shutdown mode Current Sense Signal (LTC4441) with <12µA of supply current. Undervoltage lockout and n Available in SO-8 and 10-Lead MSOP overtemperature protection circuits will disable the driver (Exposed Pad) Packages output when activated. The LTC4441 also comes with an open-drain output that provides adjustable leading edge Applications blanking to prevent ringing when sensing the source current of the power MOSFETs. n Power Supplies n Motor/Relay Control The LTC4441 is available in a thermally enhanced 10-lead n Line Drivers MSOP package. The LTC4441-1 is the SO-8 version without n Charge Pumps the blanking function. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6677210.

Typical Application L1 D1 10µH 20A MBR10100 V VOUT IN 52V RISE/FALL Time vs CLOAD 6V TO 24V + 22µF + 2A 200 25V C R1 OUT TA = 25°C X7R R5 180 DRVCC = 5V 330k VIN FB DRVCC C 160 R2 VCC SHUTDOWN Q2 R6 10µF 86.6k 140 X5R Si7370 SGND OUT ×2 120 LTC4441 100 EN/SHDN R3 RISE TIME 5mΩ 80 R7 LTC3803 RBLANK PGND RISE/FALL TIME (ns) 60 SWITCHING CONTROLLER 40 GATE IN BLANK R4 FALL TIME 20 100Ω SENSE+ 0 0 15510 20 25 30 35 454050 GND R8 CLOAD (nF)

511k 4441 TA01b FB R9 8.06k

4441 TA01a 44411fa 1 LTC4441/LTC4441-1

Absolute Maximum Ratings (Notes 1, 8) Supply Voltage OUT Output Current...... 100mA VIN...... 28V Operating Junction Temperature Range DRVCC...... 9V (Note 2)...... –55°C to 125°C Input Voltage Storage Temperature Range...... –65°C to 150°C IN...... –15V to 15V Lead Temperature (Soldering, 10 sec)...... 300°C FB, EN/SHDN...... –0.3V to DRVCC + 0.3V RBLANK, BLANK (LTC4441 Only)...... –0.3V to 5V

Pin Configuration

TOP VIEW TOP VIEW PGND 1 10 OUT PGND 1 8 OUT BLANK 2 9 DRVCC SGND 2 7 DRV RBLANK 3 11 8 VIN CC SGND 4 7 FB IN 3 6 V IN 5 6 EN/SHDN IN EN/SHDN 4 5 FB MSE PACKAGE 10-LEAD PLASTIC MSOP S8 PACKAGE TJMAX = 125°C, θJA = 38°C/W (Note 3) 8-LEAD PLASTIC SO EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB TJMAX = 125°C, θJA = 150°C/W

Order Information

LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4441EMSE#PBF LTC4441EMSE#TRPBF LTBJQ 10-Lead Plastic MSOP –40°C to 125°C LTC4441IMSE#PBF LTC4441IMSE#TRPBF LTBJP 10-Lead Plastic MSOP –40°C to 125°C LTC4441MPMSE#PBF LTC4441MPMSE#TRPBF LTBJP 10-Lead Plastic MSOP –55°C to 125°C LTC4441ES8-1#PBF LTC4441ES8-1#TRPBF 44411 8-Lead Plastic SO –40°C to 125°C LTC4441IS8-1#PBF LTC4441IS8-1#TRPBF 4441I1 8-Lead Plastic SO –40°C to 125°C LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4441EMSE LTC4441EMSE#TR LTBJQ 10-Lead Plastic MSOP –40°C to 125°C LTC4441IMSE LTC4441IMSE#TR LTBJP 10-Lead Plastic MSOP –40°C to 125°C LTC4441MPMSE LTC4441MPMSE#TR LTBJP 10-Lead Plastic MSOP –55°C to 125°C LTC4441ES8-1 LTC4441ES8-1#TR 44411 8-Lead Plastic SO –40°C to 125°C LTC4441IS8-1 LTC4441IS8-1#TR 4441I1 8-Lead Plastic SO –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/

44411fa 2 LTC4441/LTC4441-1

E lectrical Characteristics The l denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 7.5V, DRVCC = 5V, unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS l VDRVCC Driver Supply Programmable Range 5 8 V l IVIN VIN Supply Current EN/SHDN = 0V, IN = 0V 5 12 μA EN/SHDN = 5V, IN = 0V l 250 500 μA fIN = 100kHz, COUT = 4.7nF (Note 4) 3 6 mA

DRVCC Regulator l VFB Regulator Feedback Voltage VIN = 7.5V 1.11 1.21 1.31 V

ΔVDRVCC(LINE) Regulator Line Regulation VIN = 7.5V to 25V 9 40 mV

ΔVDRVCC(LOAD) Load Regulation Load = 0mA to 40mA –0.1 %

VDROPOUT Regulator Dropout Voltage Load = 40mA 370 mV

VUVLO FB Pin UVLO Voltage Rising Edge 1.09 V Falling Edge 0.97 V Input l VIH IN Pin High Input Threshold Rising Edge 2 2.4 2.8 V l VIL IN Pin Low Input Threshold Falling Edge 1 1.4 1.8 V

VIH-VIL IN Pin Input Voltage Hysteresis Rising-Falling Edge 1 V l IINP IN Pin Input Current VIN = ±10V ±0.01 ±10 μA l IEN/SHDN EN/SHDN Pin Input Current VEN/SHDN = 9V ±0.01 ±1 μA

VSHDN EN/SHDN Pin Shutdown Threshold Falling Edge 0.45 V

VEN EN/SHDN Pin Enable Threshold Rising Edge 1.21 V Falling Edge l 1.036 1.09 1.145 V

VEN(HYST) EN/SHDN Pin Enable Hysteresis Rising-Falling Edge 0.12 V Output l RONL Driver Output Pull-Down Resistance IOUT = 100mA 0.35 0.8 Ω

IPU Driver Output Peak Pull-Up Current DRVCC = 8V 6 A

IPD Driver Output Peak Pull-Down Current DRVCC = 8V 6 A

RON(BLANK) BLANK Pin Pull-Down Resistance IN = 0V, IBLANK = 100mA LTC4441 Only 11 Ω

VRBLANK RBLANK Pin Voltage RBLANK = 200kΩ LTC4441 Only 1.3 V Switching Timing tPHL Driver Output High-Low Propagation Delay COUT = 4.7nF (Note 5) 30 ns tPLH Driver Output Low-High Propagation Delay COUT = 4.7nF (Note 5) 36 ns tr Driver Output Rise Time COUT = 4.7nF (Note 5) 13 ns tf Driver Output Fall Time COUT = 4.7nF (Note 5) 8 ns tBLANK Driver Output High to BLANK Pin High RBLANK = 200kΩ (Note 6) 200 ns

Note 1: Stresses beyond those listed under Absolute Maximum Ratings guaranteed over the –40°C to 125°C operating junction temperature may cause permanent damage to the device. Exposure to any Absolute range. The LTC4441MP is guaranteed and tested over the full –55°C to Maximum Rating condition for extended periods may affect device 125°C operating junction temperature range. Note that the maximum reliability and lifetime. ambient temperature consistent with these specifications is determined by Note 2: The LTC4441/LTC4441-1 are tested under pulsed load conditions specific operating conditions in conjunction with board layout, the rated such that TJ ≈ TA. The LTC4441E/LTC4441E-1 are guaranteed to meet package thermal impedance and other environmental factors. The junction performance specifications from 0°C to 85°C operating junction temperature (TJ, in °C) is calculated from the ambient temperature temperature. Specifications over the –40°C to 125°C operating junction (TA, in °C) and power dissipation (PD, in Watts) according to the formula: temperature range are assured by design characterization and correlation TJ = TA + (PD • θJA) with statistical process controls. The LTC4441I/LTC4441I-1 grade are where θJA (in °C/W) is the package thermal impedance.

44411fa 3 LTC4441/LTC4441-1 Electrical Characteristics

Note 3: Failure to solder the Exposed Pad of the MSE package to the PC Note 6: Blanking time is measured from 50% of OUT leading edge to 10% board will result in a thermal resistance much higher than 38°C/W. of BLANK with a 1kΩ pull-up at BLANK pin. LTC4441 only. Note 4: Supply current in normal operation is dominated by the current Note 7: Guaranteed by design, not subject to test. needed to charge and discharge the external power MOSFET gate. This Note 8: This IC includes overtemperature protection that is intended to current will vary with supply voltage, switching frequency and the external protect the device during momentary overload conditions. The junction MOSFETs used. temperature will exceed 125°C when overtemperature protection is active. Note 5: Rise and fall times are measured using 10% and 90% levels. Continuous operation above the maximum operating junction temperature Delay times are measured from 50% of input to 20%/80% levels at driver may impair device reliability. output.

Typical Performance Characteristics

IN Pin Low Threshold Voltage IN Pin High Threshold Voltage EN Pin Input Threshold Voltage vs Temperature vs Temperature vs Temperature 1.8 2.8 1.30 V = 7.5V V = 7.5V V = 7.5V IN IN 1.28 IN 1.7 DRVCC = 5V 2.7 DRVCC = 5V DRVCC = 5V 1.26 1.6 2.6 1.24 1.22 RISING EDGE 1.5 2.5 1.20 1.18 1.4 2.4 1.16 1.3 2.3 1.14 1.12 FALLING EDGE 1.2 2.2 1.10 IN PIN INPUT THRESHOLD (V) IN PIN INPUT THRESHOLD (V) 1.08 1.1 2.1

EN PIN INPUT THRESHOLD VOLTAGE (V) 1.06 1.0 2.0 1.04 –75 –50 –25 025 50 75 100 125 –75 –50 –25 025 50 75 100 125 –75 –50 –25 025 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C)

4441 G01 4441 G02 4441 G03

FB Pin UVLO Threshold SD Pin Input Threshold Voltage vs Temperature vs Temperature DRVCC Voltage vs Temperature 1.20 0.80 5.50 VIN = 7.5V VIN = 7.5V R1 = 330k 1.16 0.75 DRVCC = 5V 5.45 R2 = 100k

1.12 0.70 5.40 RISING EDGE 0.65 5.35 1.08 RISING EDGE 0.60 5.30 1.04 0.55 5.25 VIN = 25V 1.00 VOLTAGE (V)

FALLING EDGE 0.50 CC 5.20 VIN = 7.5V 0.96 FALLING EDGE 0.45 DRV 5.15 0.92 0.40 5.10 0.88 FB PIN UVLO THRESHOLD VOLTAGE (V) 0.35 5.05 SD PIN INPUT THRESHOLD VOLTAGE (V) 0.84 0.30 5.00 –75 –50 –25 025 50 75 100 125 –75 –50 –25 025 50 75 100 125 –75 –50 –25 025 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C)

4441 G04 4441 G05 4441 G06

44411fa 4 LTC4441/LTC4441-1 Typical Performance Characteristics

DRVCC Dropout Voltage DRVCC Load Regulation DRVCC Line Regulation vs Temperature 5.50 5.30 1000 VIN = 7.5V TA = 25°C VIN = 7.5V 5.45 TA = 25°C R1 = 330k 900 DRVCC = 5V R1 = 330k 5.25 R2 = 100k ILOAD = 40mA 5.40 R2 = 100k 800 5.35 700 5.20 5.30 600 (V) (V)

CC 5.25 CC 5.15 500

DRV 5.20 DRV 400 5.10 5.15 DROPOUT VOLTAGE (mV) 300 CC 5.10 200

5.05 DRV 5.05 100 5.00 5.00 0 0 20 4060 80 100 120 140 160 180 200 0 5 10 15 20 25 30 –75 –50 –25 025 50 75 100 125 ILOAD (mA) VIN (V) TEMPERATURE (°C)

4441 G07 4441 G08 4441 G09

OUT Pin Pull-Down Resistance vs Temperature tPLH, tPHL vs DRVCC tPLH, tPHL vs Temperature 0.8 60 60 VIN = 7.5V TA = 25°C VDRVCC = 5V 0.7 DRVCC = 5V CLOAD = 4.7nF CLOAD = 4.7nF 50 50 0.6 40 40 0.5 tPLH tPLH (ns) (ns)

0.4 PHL 30 PHL 30 , t , t t t PHL

PLH PHL PLH

0.3 t t 20 20 0.2 10 10 0.1 OUT PIN PULL-DOWN RESISTANCE (Ω)

0 0 0 –75 –50 –25 025 50 75 100 125 4.5 5.0 5.56.0 6.5 7.0 7.5 8.0 8.5 9.0 –75 –50 –25 025 50 75 100 125 TEMPERATURE (°C) DRVCC (V) TEMPERATURE (°C)

4441 G10 4441 G11 4441 G12

tPLH, tPHL vs CLOAD RISE/FALL Time vs DRVCC RISE/FALL Time vs Temperature 100 30 30 TA = 25°C TA = 25°C VDRVCC = 5V 90 DRVCC = 5V CLOAD = 4.7nF CLOAD = 4.7nF 25 25 80 tPLH 70 20 20 60 (ns) RISE TIME

PHL 50 15 RISE TIME 15 , t t 40 PHL PLH t 10 10

30 RISE/FALL TIME (ns) FALL TIME RISE/FALL TIME (ns) FALL TIME 20 5 5 10 0 0 0 0 15510 20 25 30 35 454050 4.5 5.0 5.56.0 6.5 7.0 7.5 8.0 8.5 9.0 –50 –25 025 50 75 100 125 CLOAD (nF) DRVCC (V) TEMPERATURE (°C)

4441 G13 4441 G14 4441 G15

44411fa 5 LTC4441/LTC4441-1 Typical Performance Characteristics

RISE/FALL Time vs CLOAD Blanking Time vs RBLANK Blanking Time vs Temperature 200 500 250 TA = 25°C TA = 25°C VIN = 7.5V 180 DRVCC = 5V 450 DRVCC = 5V 240 DRVCC = 5V LTC4441 LTC4441 160 400 230 140 350 220 120 300 210 100 250 200 RISE TIME 80 200 190 RISE/FALL TIME (ns) 60 BLANKING TIME (ns) 150 BLANKING TIME (ns) 180 40 100 170 FALL TIME 20 50 160 0 0 150 0 15510 20 25 30 35 454050 0 100 200300 400 500 600 700 –75 –50 –25 025 50 75 100 125 CLOAD (nF) RBLANK (k) TEMPERATURE (°C)

4441 G16 4441 G17 4441 G18

VIN Operating Supply Current VIN Standby Supply Current vs Temperature vs Temperature 500 15 EN = 5V 14 EN = 0V 450 IN = 0V IN = 0V 13 400 12 VIN = 25V 11 350 10 300 VIN = 25V 9 8 250 7 VIN = 7.5V 6 200 VIN = 7.5V 5

SUPPLY CURRENT (µA) 150 SUPPLY CURRENT (µA) 4 IN IN V 100 V 3 2 50 1 0 0 –75 –50 –25 025 50 75 100 125 –75 –50 –25 025 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C)

4441 G19 4441 G20

IVIN vs fIN IVIN vs CLOAD 50 60 TA = 25°C TA = 25°C 45 CLOAD = 4.7nF fIN = 100kHz 50 40 35 DRVCC = 5V 40 30 DRVCC = 9V

(mA) 25 (mA) 30 VIN VIN I 20 I 20 15 DRVCC = 9V DRVCC = 5V 10 10 5 0 0 0100 200 300 400 500 600 700 9008001000 0 15510 20 25 30 35 454050 fIN (kHz) CLOAD (nF)

4441 G21 4441 G22

44411fa 6 LTC4441/LTC4441-1

Pin Functions (MSOP/SO-8)

PGND (Pin 1/Pin 1): Driver Ground. Connect the DRVCC EN/SHDN (Pin 6/Pin 4): Enable/Shutdown Input. Pulling bypass capacitor directly to this pin, as close as possible this pin above 1.21V allows the driver to switch. Pulling to the IC. In addition, connect the PGND and SGND pins this pin below 1.09V forces the driver output to go low. together close to the IC, and then connect this node to the Pulling this pin below 0.45V forces the LTC4441/LTC4441-1 source of the power MOSFET (or current sense resistor) into shutdown mode; the DRVCC regulator turns off and with as short and wide a PCB trace as possible. the supply current drops below 12μA.

BLANK (Pin 2/NA): Current Sense Blanking Output. Use FB (Pin 7/Pin 5): DRVCC Regulator Feedback Input. Connect this pin to assert a blanking time in the power MOSFET’s this pin to the center tap of an external resistive divider source current sense signal. The LTC4441 pulls this open- between DRVCC and SGND to program the DRVCC regulator drain output to SGND if the driver output is low. The output output voltage. To ensure loop stability, use the value of becomes high impedance after a programmable blanking 330kΩ for the top resistor, R1. time from the driver leading edge output. This blanking V (Pin 8/Pin 6): Main Supply Input. This pin powers the time can be adjusted with the RBLANK pin.* IN DRVCC linear regulator. Bypass this pin to SGND with a RBLANK (Pin 3/NA): Blanking Time Adjust Input. Connect 1μF ceramic, tantalum or other low ESR capacitor in close a resistor from this pin to SGND to set the blanking time. proximity to the LTC4441/LTC4441-1. A small resistor value gives a shorter delay. Leave this pin DRVCC (Pin 9/Pin 7): Linear Regulator Output. This output floating if the BLANK pin is not used.* pin powers the driver and the control circuitry. Bypass this SGND (Pin 4/Pin 2): Signal Ground. Ground return for the pin to PGND using a 10μF ceramic, low ESR (X5R or X7R) DRVCC regulator and low power circuitry. capacitor in close proximity to the LTC4441/LTC4441-1. IN (Pin 5/Pin 3): Driver Logic Input. This is the noninverting OUT (Pin 10/Pin 8): Driver Output. driver input under normal operating conditions. GND (Exposed Pad Pin 11/NA): Ground. The exposed pad must be soldered to the PCB ground. *Available only on the 10-lead version of the LTC4441.

44411fa 7 LTC4441/LTC4441-1 Block Diagram

VIN BIAS – 1.21V

REG MREG FB +

UVLO DRVCC 1.09V

IN Q1 INB P1 OUT

EN/SHDN N1 PGND EN 1.21V THERMAL SHUTDOWN LEADING RBLANK EDGE DELAY

BLANK SHDN SHUTDOWN SGND MB FOR 10-LEAD 0.45V LTC4441 ONLY

4441 BD

44411fa 8 LTC4441/LTC4441-1 Applications Information Overview VIN LTC4441

Power MOSFETs generally account for the majority of power lost in a converter. It is important to choose not only 1.21V – R1

the type of MOSFET used, but also its gate drive circuitry. 330k REG MREG The LTC4441/LTC4441-1 is designed to drive an N-channel FB + power MOSFET with little efficiency loss. The LTC4441/ R2 LTC4441-1 can deliver up to 6A of peak current using a ENABLE UVLO combined NPN Bipolar and MOSFET output stage. This DRIVER DRVCC helps to turn the power MOSFET fully “on” or “off” with 1.09V CVCC a very brief transition region. OUT DRIVER The LTC4441/LTC4441-1 includes a programmable linear- regulator to regulate the gate drive voltage. This regulator PGND provides the flexibility to use either standard threshold or 4441 F01 logic level MOSFETs. Figure 1. DRVCC Regulator

DRVCC Regulator The LTC4441/LTC4441-1 monitors the FB pin for DRVCC’s An internal, P-channel low dropout linear regulator provides UVLO condition (UVLO in Figure 1). During power-up, the driver output is held low until the DRV voltage reaches the DRVCC supply to power the driver and the pre-driver CC logic circuitry as shown in Figure 1. The regulator output 90% of the programmed value. Thereafter, if the DRVCC voltage can be programmed between 5V and 8V with an voltage drops more than 20% below the programmed value, the driver output is forced low. external resistive divider between DRVCC and SGND and a center tap connected to the FB pin. The regulator needs an R1 value of around 330k to ensure loop stability; the value Logic Input Stage of R2 can be varied to achieve the required DRVCC voltage: The LTC4441/LTC4441-1 driver employs TTL/CMOS com- 406k patible input thresholds that allow a low voltage digital R2 = signal to drive standard power MOSFETs. The LTC4441/ DRV − 1.21V CC LTC4441-1 contains an internal voltage regulator that biases the input buffer, allowing the input thresholds (V The DRVCC regulator can supply up to 100mA and is IH short-circuit protected. The output must be bypassed = 2.4V, VIL = 1.4V) to be independent of the programmed- to the PGND pin in very close proximity to the IC pins driver supply, DRVCC, or the input supply, VIN. The 1V with a minimum of 10µF ceramic, low ESR (X5R or X7R) hysteresis between VIH and VIL eliminates false triggering capacitor. Good bypassing is necessary as high transient due to noise during switching transitions. However, care supply currents are required by the driver. If the input should be taken to isolate this pin from any noise pickup, especially in high frequency, high voltage applications.The supply voltage, VIN, is close to the required gate drive voltage, this regulator can be disabled by connecting the LTC4441/LTC4441-1 input buffer has high input impedance and draws negligible input current, simplifying the drive DRVCC and FB pins to VIN. circuitry required for the input. This input can withstand voltages up to 15V above and below ground. This makes the chip more tolerant to ringing on the input digital signal caused by parasitic inductance.

44411fa 9 LTC4441/LTC4441-1 Applications Information Driver Output Stage The pre-driver that drives Q1, P1 and N1 uses an adap- A simplified version of the LTC4441/LTC4441-1’s driver- tive method to minimize cross-conduction currents. This output stage is shown in Figure 2. is done with a 5ns nonoverlapping transition time. N1 is fully turned off before Q1 is turned on and vice-versa using VIN this 5ns buffer time. This minimizes any cross-conduction DRVCC LTC4441 LOAD Q1 INDUCTOR currents while Q1 and N1 are switching on and off without P1 affecting their rise and fall times. C OUT GD POWER Thermal Shutdown N1 RO MOSFET CGS N2 The LTC4441/LTC4441-1 has a thermal detector that dis- DRVCC N3 PGND ables the DRVCC regulator and pulls the driver output low when activated. If the junction temperature exceeds150°C, 4441 F02 the driver pull-up devices, Q1 and P1, turn off while the Figure 2. Driver Output Stage pull-down device, N1, turns on briskly for 200ns to quickly pull the output low. The thermal shutdown circuit has 20°C The pull-up device is the combination of an NPN transis- of hysteresis. tor, Q1, and a P-channel MOSFET, P1. This provides both the ability to swing to rail (DRVCC) and deliver large peak Enable/Shutdown Input charging currents. The EN/SHDN pin serves two functions. Pulling this pin The pull-down device is an N-channel MOSFET, N1, with below 0.45V forces the LTC4441/LTC4441-1 into shutdown a typical on resistance of 0.35Ω. The low impedance of mode. In shutdown mode, the internal circuitry and the N1 provides fast turn-off of the external power MOSFET DRVCC regulator are off and the supply current drops to and holds the power MOSFET’s gate low when its drain <12µA. If the input voltage is between 0.45V and 1.21V, voltage switches. When the power MOSFET’s gate is pulled the DRVCC regulator and internal circuit power up but the low (gate shorted to source through N1) by the LTC4441/ driver output stays low. If the input goes above 1.21V, the LTC4441-1, its drain voltage is pulled high by its load (e.g., driver starts switching according to the input logic signal. inductor or resistor). The slew rate of the drain voltage The driver enable comparator has a small hysteresis of causes current to flow to the MOSFET’s gate through its 120mV. gate-to-drain capacitance. If the MOSFET driver does not have sufficient sink current capability (low output imped- Blanking ance), the current through the power MOSFET’s C can GD In some switcher applications, a current sense resistor momentarily pull the gate high and turn the MOSFET is placed between the low side power MOSFET’s source back on. terminal and ground to sense the current in the MOSFET. A similar situation occurs during power-up when VIN is- With this configuration, the switching controller must ramping up with the DRVCC regulator output still low. N1 is incorporate some timing interval to blank the ringing off and the driver output, OUT, may momentarily pull high onthe current sense signal immediately after the MOSFET through the power MOSFET’s CGD, turning on the power is turned on. This ringing is caused by the parasitic induc- MOSFET. The N-channel MOSFETs N2 and N3,shown in tance and capacitance of the PCB trace and the MOSFET. Figure 2, prevent the driver output from going high in this The duration of the ringing is thus dependent on the PCB situation. If DRVCC is low, N3 is off. If OUT is pulled high layout and the components used and can be longer than through the power MOSFET’s CGD, the gate of N2 gets the blanking interval provided by the controller. pulled high through RO. This turns N2 on, which then pulls OUT low. Once DRVCC is >1V, N3 turns on to hold the N2 gate low, thus disabling N2. 44411fa 10 LTC4441/LTC4441-1 Applications Information The 10-Lead LTC4441 includes an open-drain output that IN can be used to extend this blanking interval. The 8-Lead

LTC4441-1 does not have this blanking function. Figure 3 OUT shows the BLANK pin connection. The BLANK pin is connected directly to the switching controller’s SENSE+ input. POWER MOSFET’s Figure 4 shows the blanking waveforms. If the driver input CURRENT is low, the external power MOSFET is off and MB turns POWER MOSFET’s on to hold SENSE+ low. If the driver input goes high, the SOURCE TERMINAL power MOSFET turns on after the driver’s propagation delay. MB remains on, attenuating the ringing seen by the MB GATE controller’s SENSE+ input. After the programmed blanking time, MB turns off to enable the current sense signal. MB + is designed to turn on and turn off at a controlled slew rate. BLANK/SENSE This is to prevent the gate switching noise from coupling 4441 F04 into the current sense signal. BLANKING TIME

VIN Figure 4. Blanking Waveforms

TO LTC4441 LOAD INDUCTOR SWITCHING Power Dissipation CONTROLLER’S CURRENT OUT POWER DRIVER SENSE To ensure proper operation and long-term reliability, the MOSFET INPUT R4 LTC4441/LTC4441-1 must not operate beyond its maxi- + LEADING SENSE mum temperature rating. The junction temperature can EDGE DELAY R3 be calculated by: SENSE–

BLANK IQ(TOT) = IQ + ƒ • QG P = V • (I + ƒ • Q ) MB SGND D IN Q G

RBLANK PGND KEEP THIS TJ = TA + PD • θJA TRACE SHORT 4441 F03 where: R7 IQ = LTC4441/LTC4441-1 static quiescent current, Figure 3. Blanking Circuit typically 250µA The blanking interval can be adjusted using resistor R7 ƒ = Logic input switching frequency connected to the RBLANK pin. A small resistance value QG = Power MOSFET total gate charge at corre- gives a shorter interval with a default minimum of 75ns. sponding VGS voltage equal to DRVCC

The value of the resistor R4 and the on-resistance of MB VIN = LTC4441/LTC4441-1 input supply voltage (typically 11Ω) form a resistive divider attenuating the T = Junction temperature ringing. R4 needs to be large for effective blanking, but not J so large as to cause delay to the sense signal. A resistance TA = Ambient temperature value of 1k to 10k is recommended. θJA = Junction-to-ambient thermal resistance. The For optimum performance, the LTC4441/LTC4441-1should 10-pin MSOP package has a thermal resistance of be placed as close as possible to the powerMOSFET and θJA = 38°C/W. current sense resistor, R3.

44411fa 11 LTC4441/LTC4441-1 Applications Information

The total supply current, IQ(TOT), consists of the LTC4441/ PC Board Layout Checklist LTC4441-1’s static quiescent current, I , and the current Q When laying out the printed circuit board, the following- required to drive the gate of the power MOSFET, with checklist should be used to ensure proper operation of thelatter usually much higher than the former. The dissi- the LTC4441/LTC4441-1: pated power, PD, includes the efficiency loss of the DRVCC regulator. With a programmed DRVCC, a high VIN results A. Mount the bypass capacitors as close as possible be- in higher efficiency loss. tween the DRVCC and PGND pins and between the VIN and SGND pins. The PCB trace loop areas should be = 12V. As an example, consider an application with VIN tightened as much as possible to reduce inductance. The switching frequency is 300kHz and the maximum ambient temperature is 70°C. The power MOSFET chosen B. Use a low inductance, low impedance ground plane to is three pieces of IRFB31N20D, which has a maximum reduce any ground drop. Remember that the LTC4441/ RDS(ON) of 82mΩ (at room temperature) and a typical LTC4441-1 switches 6A peak current and any significant total gatecharge of 70nC (the temperature coefficient of ground drop will degrade signal integrity. the gate charge is low). C. Keep the PCB ground trace between the LTC4441/ IQ(TOT) = 500µA + 210nC • 300kHz = 63.5mA LTC4441-1 ground pins (PGND and SGND) and the external current sense resistor as short and wide as P = 12V • 63.5mA = 0.762W IC possible. T = 70°C + 38°C/W • 0.762W = 99°C J D. Plan the ground routing carefully. Know where the large This demonstrates how significant the gate charge cur- load switching current paths are. Maintain separate rent can be when compared to the LTC4441/LTC4441-1’s ground return paths for the input pin and output pin static quiescent current. To prevent the maximum junc- to avoid sharing small-signal ground with large load tion temperature from being exceeded, the input supply ground return. Terminate these two ground traces only current must be checked when switching at high VIN. A at the GND pin of the driver (STAR network). tradeoff between the operating frequency and the size of E. Keep the copper trace between the driver output pin the power MOSFET may be necessary to maintain areliable andthe load short and wide. LTC4441/LTC4441-1 junction temperature. Prior to lower- ing the operating frequency, however, be sure to check with F. Place the small-signal components away from the high power MOSFET manufacturers for their innovations on low frequency switching nodes. These components include QG, low RDS(ON) devices. Power MOSFET manufacturing the resistive networks connected to the FB, RBLANK technologies are continually improving, with newer and and EN/SHDN pins. better performing devices being introduced.

44411fa 12 LTC4441/LTC4441-1 Package Description MSE Package 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1664 Rev G)

BOTTOM VIEW OF EXPOSED PAD OPTION 1.88 1.88 ± 0.102 (.074 ± .004) 0.889 ± 0.127 1 (.074) 0.29 (.035 ± .005) 1.68 REF (.066)

5.23 0.05 REF 1.68 ± 0.102 3.20 – 3.45 (.206) DETAIL “B” (.066 ± .004) (.126 – .136) MIN CORNER TAIL IS PART OF DETAIL “B” THE LEADFRAME FEATURE. FOR REFERENCE ONLY 10 NO MEASUREMENT PURPOSE 0.50 0.305 ± 0.038 (.0197) 3.00 ± 0.102 (.0120 ± .0015) BSC (.118 ± .004) 0.497 ± 0.076 TYP (NOTE 3) (.0196 ± .003) RECOMMENDED SOLDER PAD LAYOUT 8910 7 6 REF

3.00 0.102 4.90 ± 0.152 ± (.118 .004) (.193 ± .006) ± (NOTE 4) DETAIL “A” 0.254 (.010) 0° – 6° TYP GAUGE PLANE 1 2 3 4 5

0.53 ± 0.152 1.10 0.86 (.021 ± .006) (.043) (.034) MAX REF DETAIL “A” 0.18 (.007) SEATING PLANE 0.17 – 0.27 0.1016 ± 0.0508 (.007 – .011) (.004 .002) 0.50 ± TYP MSOP (MSE) 0910 REV G NOTE: (.0197) 1. DIMENSIONS IN MILLIMETER/(INCH) BSC 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 6. EXPOSED PAD DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL NOT EXCEED 0.254mm (.010") PER SIDE.

44411fa 13 LTC4441/LTC4441-1 Package Description S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610)

.189 – .197 .045 ±.005 (4.801 – 5.004) .050 BSC NOTE 3 8 7 6 5

.245 .160 .005 MIN ± .150 – .157 .228 – .244 (3.810 – 3.988) (5.791 – 6.197) NOTE 3

.030 ±.005 TYP 1 2 3 4 RECOMMENDED SOLDER PAD LAYOUT

.010 – .020 × 45° .053 – .069 (0.254 – 0.508) (1.346 – 1.752) .004 – .010 .008 – .010 (0.101 – 0.254) (0.203 – 0.254) 0°– 8° TYP

.016 – .050 .014 – .019 .050 (0.406 – 1.270) (0.355 – 0.483) (1.270) NOTE: INCHES TYP BSC 1. DIMENSIONS IN (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) SO8 0303

44411fa 14 LTC4441/LTC4441-1 Revision History

REV DATE DESCRIPTION PAGE NUMBER A 03/11 Added MP-grade part. Changes reflected throughout the data sheet. 1-16

44411fa

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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LTC4441/LTC4441-1 Related Parts

PART NUMBER DESCRIPTION COMMENTS

LTC4440/ High Voltage, High Speed, High Side N-Channel Up to 80V Supply Voltage, 8V ≤ VCC ≤ 15V, LTC4440-5 Gate Driver 2.4A Peak Pull-Up/1.5Ω Peak Pull-Down

LTC4442 High Speed Synchronous N-Channel MOSFET Driver Up to 38V Supply Voltage, 6V ≤ VCC ≤ 9.5V

LTC4449 High Speed Synchronous N-Channel MOSFET Driver Up to 38V Supply Voltage, 4.5V ≤ VCC ≤ 6.5V

LTC4444/ High Voltage Synchronous N-Channel MOSFET Driver Up to 100V Supply Voltage, 4.5V/7.2V ≤ VCC ≤ 13.5V, LTC4444-5 with Shoot Thru Protection 3A Peak Pull-Up/0.55Ω Peak Pull-Down

LTC4446 High Voltage Synchronous N-Channel MOSFET Driver Up to 100V Supply Voltage, 7.2V ≤ VCC ≤ 13.5V, without Shoot Thru Protection 3A Peak Pull-Up/0.55Ω Peak Pull-Down LTC1154 High Side Micropower MOSFET Driver Up to 18V Supply Voltage, 85µA Quiescent Current, Internal Charge Pump

44411fa Linear Technology Corporation LT 0311 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 16 ● ● (408) 432-1900 FAX: (408) 434-0507 www.linear.com  LINEAR TECHNOLOGY CORPORATION 2004