LT3932-1

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Rev. 0For more information www.analog.com Document Feedback All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 10291128, 10136488, 9642200. TYPICAL APPLICATION FEATURES DESCRIPTION 60V, 3A Silent Switcher Synchronous, Step-Up LED Driver The LT®8386 is a monolithic, synchronous, step-up DC-to-DC converter that utilizes fixed frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or digital pulses at the CTRL pin. The LT8386 will maintain 2% current regulation through an external sense resistor over a wide range of output voltages. The LT8386 features Silent Switcher ® technology designed to minimize EMI/EMC emissions with high effi- ciency. The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock applied at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT8386 includes a driver for an external high side PMOS for PWM dimming. The 60V rated LT8386 is pin- to-pin compatible with the LT3922 and LT3922-1. 2MHz, 90% Efficient 14W (47V, 300mA) Boost LED Driver Efficiency vs VIN

APPLICATIONS

n Automotive and Industrial Lighting n Heads Up Display (HUD)/Machine Vision n 2% LED Current Regulation n 2.5% Output Voltage Regulation n 50,000:1 PWM Dimming at 100Hz n 512:1 Internal PWM Dimming n Spread Spectrum Frequency Modulation n Silent Switcher Architecture for Ultralow EMI n Operates in Boost, Buck Mode and Buck-Boost Mode n 4V to 56V Input Voltage Range n Up to 52V LED String Voltage n Adaptive Peak Switch Current Limit Up to 5A for Low VIN n 200kHz to 2MHz with SYNC Function n Analog or Duty Cycle LED Current Control n Open/Short LED Protection and Fault Indication n Small 28-Lead 4mm × 5mm LQFN Package n AEC-Q100 Qualified for Automotive Applications L T8386

8386 TA01a

4.7µH VOUT FB GND ISP ISN PWMTG ISMON EN/UVLO OVLO VREF 100k 100k CTRL PWM ANALOG DIM PWM DIM SYNC/SPRD INTVCC FAUL T SW BST 499k 140k VC 100nF 4.7nF 4.7µF 50V 333m/uni03A9 VIN 8V TO 26V 45.3k 2MHz 47V 300mA LED10k 549k 12.1k 0.1µF 100V 28k 10µF 100V 33nF 1µF 2.2µF 100% PWM DUTY CYCLE V LED = 47V f SW = 2MHz V IN (V) 100 EFFICIENCY (%)

8386 TA01b

Rev. 0 For more information www.analog.com PIN CONFIGURATIONABSOLUTE MAXIMUM RATINGS CTRL, OVLO, PWM, SYNC/SPRD, and FAUL T ...−0. 3V to 5V SW , BST , INTVCC, VREF, ISMON, PWMTG, RT , Operating Junction Temperature Range (Notes 3, 4) LT8 Maximum Reflow (Package Body) Te 0°C (Note 1) TOP VIEW LQFN PACKAGE 28-LEAD (4mm × 5mm) θJA = 25°CW (AS MEASURED ON DEMO BOARD) EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB SW BST INTVCC VIN EN/UVLO OVLO VREF CTRL GND VOUT PWMTG PWM RP SYNC/SPRD RT FAULT SW SW V OUT GND ISP ISN VC FB SS ISMON 9 10 11 12 13 14 28 27 24 23 GND ORDER INFORMATION PARAMETER CONDITIONS MIN TYP MAX UNITS Input Voltage Range 4 56 V VIN Pin Quiescent Current VEN/UVLO = 1.5V, Not Switching VEN/UVLO = 0.3V, Shutdown 3.5 4.5 1.5 mA µA EN/UVLO Threshold (Falling) 1.280 1.330 1.420 V PART NUMBER PART MARKING* FINISH CODE PAD FINISH PACKAGE TYPE MSL RATING TEMPERATURE RANGE LT8386EV#PBF 8386 e4 Au (RoHS) LQFN (Laminate Package with QFN Footprint) 3 –40°C to 125°C LT8386JV#PBF –40°C to 150°C AUTOMOTIVE PRODUCTS LT8386EV#WPBF 8386 e4 Au (RoHS) LQFN (Laminate Package with QFN Footprint) 3 –40°C to 125°C LT8386JV#WPBF –40°C to 150°C

• Contact the factory for parts specified with wider operating temperature ranges. *Device temperature grade is identified by a label on the shipping container . Pad or ball finish code is per IPC/JEDEC J-STD-609.
• Recommended LGA and BGA PCB Assembly and Manufacturing Procedures LGA and BGA Package and Tray Drawings Parts ending with PBF are RoHS and WEEE compliant. **The LT8386 packages has the same footprint as a standard 4mm × 5mm QFN Package. Versions of this part are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. These models are designated with a #W suffix. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, VEN/UVLO = 2V unless otherwise noted.

Rev. 0For more information www.analog.com ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, VEN/UVLO = 2V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS EN/UVLO Rising Hysteresis 25 mV EN/UVLO Pin Current VEN/UVLO = 1.2V 2 µA OVLO Threshold (Rising) 1.145 1.205 1.265 V OVLO Falling Hysteresis 50 mV OVLO Pin Current VOVLO = 1V –1 1 µA Reference VREF Voltage IVREF = 0µA IVREF = 1mA l 1.970 1.975 2.030 2.010 V V V REF Pin Current Limit VREF = 0V, Current Out of Pin 2 mA LED Current Regulation CTRL-Off Threshold (Falling) l 190 210 230 mV CTRL-Off Rising Hysteresis 15 mV CTRL Pin Current VCTRL = 2V –100 100 nA Sense Voltage (VISP − VISN) (Analog Input) VCTRL = 2V (100%), VISP = 24V VCTRL = 0.75V (50%), VISP = 24V VCTRL = 0.35V (10%), VISP = 24V VCTRL = 0.30V (5%), VISP = 24V l 98 48.5 100 102 51.5 11.5 6.5 mV mV mV mV ISP Pin Current V ISP = 24.1V, VISN = 24V, VCTRL = 2V 75 µA ISN Pin Current VISP = 24.1V, VISN = 24V, VCTRL = 2V 75 µA Current Error Amplifier T ransconductance V ISP = 24V 140 µA/V Duty Cycle Control of LED Current Sense Voltage (VISP − VISN) (Duty Cycle Input) CTRL Duty = 75% (100%), VISP = 24V CTRL Duty = 37.5% (50%), VISP = 24V CTRL Duty = 17.5% (10%), VISP = 24V CTRL Duty = 15.0% (5%), VISP = 24V 48.5 100 101 51.5 mV mV mV mV Digital CTRL Input High (V IH) 1.6 V Digital CTRL Input Low (VIL) 0.4 V Digital CTRL Input Frequency Range 10 200 kHz Voltage Regulation FB Regulation Voltage VCTRL = 2V l 1.170 1.200 1.230 V FB Pin Current FB in Regulation –100 100 nA Voltage Error Amplifier T ransconductance 1000 µA/V INTVCC Regulator INTVCC Voltage 3.4 3.6 3.8 V INTVCC Pin Current Limit VINTVCC = 0V, Current Out of Pin 40 mA Power Stage Peak Switch Current Limit V IN = 9V VIN = 5V 3.3 4.0 3.6 5.0 4.0 5.5 A A Bottom Switch Minimum Off-Time 13 25 30 ns Bottom Switch On-Resistance 80 mΩ Top Switch On-Resistance 130 mΩ Oscillator Programmed Switching Frequency (fSW) R T = 45.3k, SYNC/SPRD = 0V RT = 499k, SYNC/SPRD = 0V l l 1900 180 2000 210 2100 240 kHz kHz

Rev. 0 For more information www.analog.com PARAMETER CONDITIONS MIN TYP MAX UNITS Maximum Spread Spectrum Ratio SYNC/SPRD = 3V 125 % RT Pin Current Limit VRT = 0V, Current Out of Pin 75 µA SYNC/SPRD Input High (VIH) 1.6 V SYNC/SPRD Input Low (VIL) 0.8 V SYNC/SPRD Pin Current VSYNC/SPRD = 5V –100 100 nA Soft-Start SS Pin Charging Current VSS = 1V 22 µA SS Pin Discharging Current VSS = 2V 2 µA SS Lower Threshold 0.2 V SS Higher Threshold 1.55 V Fault Detection Open-Circuit Threshold (FB Rising) l 1.117 1.140 1.163 V Open-Circuit Falling Hysteresis 50 mV LED Short-Circuit Threshold (VISP − VISN) V ISP = 20V 150 mV FAUL T Pull-Down Current VFAUL T = 0.2V, VFB = 1.25V 0.8 mA FAUL T Leakage Current VFAUL T = 3.6V, VFB = 0.7V –100 100 nA Overvoltage Protection FB Overvoltage Threshold (Rising) l 1.240 1.266 1.292 V FB Overvoltage Falling Hysteresis 22 mV LED Current Monitor ISMON Pin Voltage V ISP − VISN = 100mV (100%), VISP = 24V VISP − VISN = 10mV (10%), VISP = 24V VISP − VISN = 5mV (5%), VISP = 24V 0.980 1.000 100 1.020 120 V mV mV PWM Driver P WMTG Gate Drive (VOUT – VPWMTG) V OUT = 20V, VPWM = 2V 10.5 12.5 V PWM Input High (VIH) 1.7 V PWM Input Low (VIL) 0.8 V PWM Pin Current VPWM = 2V –100 100 nA PWM to PWMTG Propagation Delay Turn-On Turn-Off CPWMTG = 2.1nF (Connected from VOUT to PWMTG) VOUT = 20V 100 140 ns ns Internal PWM Dimming Preset P WM Dimming Ratio 1 Preset PWM Dimming Ratio 2 Preset PWM Dimming Ratio 3 RP = 332k, VREF = 2V, VPWM: 0.25V to 0.35V RP = 332k, VREF = 2V, VPWM: 0.47V to 0.55V RP = 332k, VREF = 2V, VPWM: 0.65V to 0.75V l l l 1.0 4.9 9.8 1.1 9.9 1.2 5.1 PWM V oltage for 100% PWM Dimming R P = 332k, VREF = 2V 2.00 V PWM Voltage for 0% PWM Dimming R P = 332k, VREF = 2V 0.86 0.98 0.14 V V PWM Dimming Accuracy R P = 332k, VREF = 2V, VPWM = 1.1V RP = 332k, VREF = 2V, VPWM = 1.9V 88.5 91.5 PWM Dimming Frequency R P = 76.8k, RT = 45.3k, SYNC/SPRD = 0V RP = 332k, RT = 45.3k, SYNC/SPRD = 0V 1.80 110 1.95 125 2.10 135 kHz Hz RP Pin Current Limit VRP = 0V, Current Out of Pin 70 µA ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, VEN/UVLO = 2V unless otherwise noted.

Rev. 0For more information www.analog.com Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Do not apply a positive or negative voltage source to these pins, otherwise permanent damage may occur . Note 3: The LT8386E is guaranteed to meet performance specifications from 0°C to 125°C junction temperature. Specifications over the −40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LT8386J specifications over the −40°C to 150°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. Note 4: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. The maximum rated junction temperature will be exceeded when this protection is active. Continuous operation above the specified absolute maximum operating junction temperature may impair device reliability or permanently damage the device.

ELECTRICAL CHARACTERISTICS

Rev. 0 For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS EN/UVLO Thresholds EN/UVLO Pin Current OVLO Thresholds VIN Shutdown Current Distribution V IN Quiescent Current INTVCC Voltage VREF Voltage VREF Load Regulation INTVCC and VREF UVLO Falling Thresholds VIN = 12V, TA = 25°C unless otherwise noted. RISING FALLING TEMPERATURE (°C) –50 –25 100 125 150 1.20 1.25 1.30 1.35 1.40 1.45 1.50 EN/UVLO THRESHOLD (V) EN/UVLO Thresholds 8386S G01 V EN/UVLO = 1.2V TEMPERATURE (°C) –50 –25 100 125 150 1.0 1.5 2.0 2.5 3.0 3.5 4.0 EN/UVLO PIN CURRENT (µA) EN/UVLO Pin Current 8386S G02 RISING FALLING TEMPERATURE (°C) –50 –25 100 125 150 1.05 1.10 1.15 1.20 1.25 1.30 1.35 OVLO THRESHOLD (V) OVLO Thresholds 8386S G03 N = 771 150°C 25°C –40°C V IN SHUTDOWN CURRENT (uA) 0.4 0.5 0.6 0.7 0.8 0.9 1.0 100 200 300 400 500 600 700 800 NUMBER OF PARTS V IN Shutdown Current Distribution

8386 G04

TEMPERATURE (°C) –50 –25 100 125 150 2.0 2.5 3.0 3.5 4.0 4.5 5.0 V IN QUIESCENT CURRENT (mA) V IN Quiescent Current 8386S G05 V IN = 56V V IN = 12V V IN = 3V TEMPERATURE (°C) –50 –25 100 125 150 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 INTV CC VOL TAGE (V) INTV CC Voltage 8386S G06 125°C –50°C 25°C V REF LOAD CURRENT (µA) 200 400 600 800 1000 1200 1400 1600 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 V REF VOL TAGE (V) REF

8386 G08

V REF UVLO TEMPERATURE (°C) –50 –25 100 125 150 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 THRESHOLD VOL TAGE (V) Thresholds

8386 G09

TEMPERATURE (°C) –50 –25 100 125 150 1.97 1.98 1.99 2.00 2.01 2.02 V REF VOL TAGE (V) V REF Voltage

8386 G07

Rev. 0For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS LED Current (Analog CTRL) LED Current (Digital CTRL) Normalized Average LED Current vs PWM On-Time 100% Current Regulation 5% Current Regulation LED Current Line Regulation LED Current vs VOUT LED Voltage Limit Regulated FB Voltage VIN = 12V, TA = 25°C unless otherwise noted. V CTRL (V) 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 100 125 V ISP ISN (mV)

8386 G10

PULSE FREQUENCY AT CTRL PIN = 20kHz D CTRL (%) 12.5 37.5 62.5 87.5 100 100 125 V ISP ISN (mV) LED Current (Digital CTRL)

8386 G11

PWM FREQUENCY = 200Hz CTRL = 2.00V (100%) CTRL = 0.75V (50%) CTRL = 0.30V (5%) PWM ON TIME (/uni03BCs) 0.01 0.1 100 10k 0.0001 0.001 0.01 0.1 100 NORMALIZED I LED (%) vs PWM ON Time

8386 G12

N = 771 V CTRL = 2V V ISP = 24V 150°C 25°C –40°C ISP–ISN VOL TAGE (mV) 99.5 100 100.5 101 100 200 300 400 500 600 700 800 NUMBER OF UNITS 100% Current Regulation 8386S G13 N = 771 V CTRL = 0.3V V ISP = 24V 150°C 25°C –40°C ISP–ISN VOL TAGE (mV) 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 100 200 300 400 500 600 700 800 NUMBER OF UNITS 5% Current Regulation 8386S G14 PEAK SW CURRENT LIMITED f SW = 2MHz R SNS = 0.3Ω

16 LEDs(V

~ 48V) V IN (V) 100 150 200 250 300 350 400 I LED (mA) LED Current Line Regulation

8386 G15

V FB OVERVOL TAGE PROTECTION LIMITED V IN = 12V f SW = 2MHz R SNS = 0.3Ω R FB_TOP = 1M R FB_BOT = 22.1k V OUT (V) 100 150 200 250 300 350 400 I LED (mA) OUT

8386 G16

V CTRL = 2V V FB (V) 1.17 1.18 1.19 1.20 1.21 1.22 100 125 V ISP – V ISN (mV) LED Voltage Limit

8386 G17

TEMPERATURE (°C) –50 –25 100 125 150 1.18 1.19 1.20 1.21 1.22 1.23 FB VOL TAGE (V) Regulated FB Voltage

8386 G18

Rev. 0 For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS FB Open-LED Threshold FB OVLO Threshold VISP – VISN Short-LED Threshold Soft-Start Currents Soft-Start Thresholds ISMON Voltage Peak SW Current Limit vs VIN Switching Frequency Minimum Off-Time VIN = 12V, TA = 25°C unless otherwise noted. RISING FALLING TEMPERATURE (°C) –50 –25 100 125 150 0.95 1.00 1.05 1.10 1.15 1.20 1.25 FB OPENLED THRESHOLD (V) FB OPENLED Threshold 8386S G19 RISING FALLING TEMPERATURE (°C) –50 –25 100 125 150 1.18 1.20 1.22 1.24 1.26 1.28 1.30 1.32 FB OVLO THRESHOLD (V) FB OVLO Threshold 8386S G20 TEMPERATURE (°C) –50 –25 100 125 150 120 130 140 150 160 170 180 V ISP – V ISN SHORTLED THRESHOLD (mV) V ISP – V ISN SHORTLED Threshold

8386 G21

PULL–UP PULL–DOWN TEMPERATURE (°C) –50 –25 100 125 150 CURRENT (µA) Soft–Start Currents 8386S G22 SS HIGH RISING SS LOW FALLING TEMPERATURE (°C) –50 –25 100 125 150 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 THRESHOLD VOL TAGE (V) Soft–Start Thresholds 8386S G23 V ISP ISN (mV) 100 200 400 600 800 1000 V ISMON (mV) ISMON Voltage

8386 G24

100°C –40°C 25°C V IN (V) PEAK SW CURRENT LIMIT (A) Peak SW Current Limit vs V IN

8386 G25

R T = 45.3k R T = 499k TEMPERATURE (°C) –50 –25 100 125 150 1400 1500 1600 1700 1800 1900 2000 2100 2200 180 190 200 210 220 230 240 250 260 SWITCHING FREQUENCY (kHZ) Switching Frequency

8386 G26

TEMPERATURE (°C) –50 –25 100 125 150 MINIMUM OFF TIME (ns) Minimum Off Time

8386 G27

Rev. 0For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS Internal PWM Dimming Internal PWM Frequency Internal PWM Dimming (10%) Preset 1 PWM Duty Cycle (1%) Preset 2 PWM Duty Cycle (5%) Preset 3 PWM Duty Cycle (10%) PWMTG On Voltage PWMTG Driver Propagation Delay RT and RP Pin Current Limits VIN = 12V, TA = 25°C unless otherwise noted. N = 713 150°C 25°C –40°C PWM DIMMING (%) 9.5 10.5 100 200 300 400 500 NUMBER OF UNITS Internal PWM Dimming (10%) 8386S G30 N = 713 150°C 25°C –40°C PWM DUTY CYCLE (%) 1.02 1.04 1.06 1.08 1.10 1.12 1.14 100 200 300 400 500 600 700 800 NUMBER OF UNITS Preset 1 PWM Duty Cycle (1%) 8386S G31 N = 713 150°C 25°C –40°C PWM DUTY CYCLE (%) 4.90 4.92 4.94 4.96 4.98 5.00 5.02 5.04 100 200 300 400 500 600 700 800 NUMBER OF UNITS Preset 2 PWM Duty Cycle (5%) 8386S G32 N = 713 150°C 25°C –40°C PWM DUTY CYCLE (%) 9.74 9.78 9.82 9.86 9.90 9.94 100 200 300 400 500 600 700 800 NUMBER OF UNITS Preset 3 PWM Duty Cycle (10%) 8386S G33 TEMPERATURE (°C) –50 –25 100 125 150 V OUT PWMTG (V) PWMTG ON Voltage

8386 G34

TEMPERATURE (°C) –50 –25 100 125 150 MAXIMUM PIN CURRENT (µA) RT and RP Pin Current Limits 8386S G36 R T = 45.3k R P = 332k R VREF–PWM = 18.2k R PWM–GND = 22.1k TEMPERATURE (°C) –50 –25 100 125 150 9.0 9.1 9.2 9.3 9.4 9.5 9.6 INTERNAL PWM DIMMING DUTY CYCLE (%) Internal PWM Dimming

8386 G28

R T = 45.3k R P = 76.8k R P = 332k TEMPERATURE (°C) –50 –25 100 125 150 1600 1680 1760 1840 1920 2000 2080 110 115 120 125 130 135 140 INTERNAL PWM FREQUENCY (Hz) Internal PWM Frequency

8386 G29

C PWMTG = 2.2nF (COG type) TURN OFF TURN ON TEMPERATURE (°C) –50 –25 100 125 150 100 120 140 160 180 200 PROPEGATION DELAY (ns) PWMTG Driver Propogation Delay

8386 G35

Rev. 0 For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS C/10 Threshold Case Temperature Rise Power Switch On-Resistance Efficiency vs VIN Efficiency vs ILED Input Voltage T ransient Response VIN = 12V, TA = 25°C unless otherwise noted. RISING FALLING TEMPERATURE (°C) –50 –25 100 125 150 V ISP – V ISN THRESHOLD (mV) C/10 Threshold

8386 G37

V LED = 48V I LED = 333mA T ROOM = 25°C f SW = 2MHz f SW = 400kHz V IN (V) CASE TEMPERATURE RISE (°C) Case Temperature Rise

8386 G38

I LED = 333mA, V LED ~ 48V (16 LEDs) f SW = 400kHz f SW = 2MHz V IN (V) 100 EFFICIENCY (%) IN

8386 G40

V IN = 12V f SW = 2MHz

7 LEDs (V

~ 20V)

10 LEDs (V

~30V)

13 LEDs (V

~40V)

17 LEDs (V

~50V) I LED (mA) 300 600 900 1200 1500 100 EFFICIENCY (%) LED

8386 G41

8V TO 16V INPUT VOL TAGE TRANSIENT V LED = 39V (13 LEDs) I LED = 500mA 5ms/DIV I LED 200mA/DIV V IN 4V/DIV

8386 G42

TEMPERATURE (°C) –50 –25 100 125 150 100 150 200 250 300 350 POWER SWITCH ON–RESISTANCE (mohm) Power Switch On–Resistance

8386 G39

Rev. 0For more information www.analog.com PIN FUNCTIONS SW (Pins 1, 27, 28): Switch Pins. These pins are inter - nally connected to the power devices and high-side gate driver . They should always be tied together . In normal operation, the voltage of these pins will switch between the output voltage and zero at the programmed frequency. Do not force any voltage on these pins. BST (Pin 2): Boost Pin. This pin supplies the top power switch GATE driver . Connect a 33nF capacitor between this pin and the SW pin as close as possible to the pack- age. An internal diode from INTVCC to BST will charge the capacitor when the SW pin switches low. INTVCC (Pin 3): Internally Regulated, Low Voltage Supply Pin. This pin provides the power for the converter switch GATE drivers. Do not force any voltage on this pin. Place a 2.2μF bypass capacitor to GND close to the package. V IN (Pin 4): Input Voltage Pin. This pin supplies power to the internal, high performance analog circuitry. Connect a bypass capacitor between this pin and GND. EN/UVLO (Pin 5): Enable and Undervoltage Lockout Pin. A voltage at this pin greater than 1.36V (typ.) will enable switching, and a voltage less than 0.1V is guaranteed to shutdown the internal current bias and sub regulators. A resistor network between this pin and ground can be used to set the pin voltage and automatically lockout the part when V IN is below a certain level. No internal com - ponents pull up or down on this pin, so it requires an external voltage bias for normal operation. This pin may be tied directly to V IN. For more details, see Applications Information section. OVLO (Pin 6): Input Overvoltage Lockout Pin. When the voltage at this pin rises above 1.205V, the system dis - ables switching and resets the soft-start capacitor . Do not leave this pin open. Tie this pin to GND when the OVLO function is not used. For more details, see Applications Information section. VREF (Pin 7): Reference Voltage Pin. This pin provides a buffered 2V reference. It can be used to supply resis- tor networks for setting the voltages at the CTRL and PWM pins. Bypass with a 0.1μF capacitor to GND. CTRL (Pin 8): Control Pin. An analog voltage from 250mV to 1.25V at this pin programs the regulated voltage between ISP and ISN (and therefore, the regulated cur - rent supplied to the load). Depending on the applications, the CTRL pin can be affected by the noise in the system. A 10nF bypass capacitor at the CTRL pin can boost the noise immunity. Alternatively, a digital pulse at this pin with duty ratio from 12.5% to 62.5% can be used to program the regulated voltage. Below 200mV or 10% duty cycle, the CTRL pin voltage disables switching. For more detail, see Typical Performance Characteristics and Applications Information sections. ISP (Pin 9): Positive Current Sense Pin. This pin is one of the inputs to the internal current sense error amplifier . It should be connected to the positive side of the external sense resistor . Use a Kelvin connection to the sense resis- tor for accurate current sensing. ISN (Pin 10): Negative Current Sense Pin. This pin is one of the inputs to the internal current sense error amplifier . It should be connected to the negative side of the external sense resistor . Use a Kelvin connection to the sense resis- tor for accurate current sensing. VC (Pin 11): Compensation Pin. A resistor and capaci - tor connected in series from this pin to GND stabilize the current and voltage regulation. Typical resistor and capacitor values are from 0 to 100kΩ and from 10nF to 0.1nF, respectively. FB (Pin 12): Feedback Pin. When the voltage at this pin is near 1.2V the regulated current is automatically reduced from the programmed value. A resistor network between this pin and V OUT can be used to set a limit for the output voltage. If the voltage at the FB pin reaches 1.266V, a FB overvoltage lockout comparator disables switching. SS (Pin 13): Soft-Start Pin. At start-up and recovery from fault conditions, a 22μA current charges the capacitor and the FB voltage tracks the rising voltage at this pin until the load current reaches its programmed level. Typical values for the capacitor are 10nF to 100nF. Using a single resistor from SS to INTVCC, the LT8386 can be set in two different fault modes for the shorted LED conditions: hiccup (no resistor) and latchoff (<470kΩ). Refer to the Applications Information section for a detailed explanation.

Rev. 0 For more information www.analog.com PIN FUNCTIONS ISMON (Pin 14): Output Current Monitoring Pin. This pin provides a buffered voltage output equal to 10mV for every 1mV between ISP and ISN. FAUL T (Pin 15): Fault Pin. Connect to INTVCC through a resistance of 100k. An internal switch pulls this pin low when any of following conditions happen: 1. Open LED: VFB > 1.14V and (VISP – VISN) < 10mV 2. Shorted LED: (VISP – VISN) > 150mV for more than 300µs, or (VISP – VISN) > 0.7V RT (Pin 16): Timing Resistor Pin. A resistor from this pin to GND programs the switching frequency between 200kHz and 2MHz. Do not leave this pin open. SYNC/SPRD (Pin 17): Synchronization Pin. To override the programmed switching frequency, drive this pin with an external clock having a frequency between 200kHz and 2MHz. Even when using the external clock, select an R T resistor that corresponds to the desired switching fre - quency. Tie the pin to INTVCC to enable spread spectrum frequency modulation. This pin should be tied to GND when not in use. RP (Pin 18): PWM Resistor Pin. Connect a resistor from this pin to GND to set the frequency of the internal PWM signal. Do not use a resistor larger than 1MΩ. If using an external PWM pulse for LED dimming, tie this pin to GND. Refer to the Applications Information section for a detailed explanation. PWM (Pin 19): PWM Input Pin. With the RP pin tied to GND, drive this pin with a digital pulse to control PWM dimming of the LEDs. Alternatively, set the voltage of this pin between 1V and 2V to generate an internal pulse with duty cycle between 0% and 100%. The LT8386 also fea- tures preset PWM dimming ratios 1, 2, and 3 that gener- ate very precise and consistent PWM ratios of 1%, 5%, and 10%, when the PWM pin voltages are 0.3V, 0.5V, and 0.7V, respectively. When using an analog signal, put a 1µF bypass capacitor between this pin and GND. PWMTG (Pin 20): PWM Driver Output Pin. This pin can drive the gate of an external high-side PMOS device for PWM dimming of LEDs or output short protection. Do not force any voltage on this pin. VOUT (Pins 21, 24): Output Pins. Connect to the output and place output capacitors between this pin and GND as close as possible to the package. Refer to the Applications Information section for the recommended capacitor placements. GND (Pins 22, 23, Exposed Pad Pin 29): Ground Pins. All GND pins must be soldered to the board ground plane. Corner Pins: These pins are for mechanical support only and can be tied anywhere on the PCB.

Rev. 0For more information www.analog.com BLOCK DIAGRAM 8386 BD – + – + –+ + CONTROL BUFFER gm = 140µA/V CURRENT REGULATION AMPLIFIER A/D DETECT INTERNAL VCC REGULATOR UVLO AND OVLO 200kHz TO 2MHz OSCILLATOR V/I CONVERTER FB REF VC REF INTERNAL PWM SIGNAL SOFT-START AND LED FAUL T CONTROL PWMTG DRIVER R Q MBSW MTSW S SYNCHRONOUS CONTROLLER PEAK CURRENT COMPARATOR 2V REFERENCE OVLO EN/UVLO GND RT CTRL SS 100nF 4.7nF 10k 22µA 2µA PWMTG VIN 499k 140k INTVCC PWM 200m/uni03A9 28k 45.3k 25k 1.2V 2.5k 10x 2.5k 0.25V 1.25V 1/uni03BCF 1.5V SYNC/SPRD VOUT 10µF GND (EXPOSED PAD) VOUT VREF VIN INTVCC BST SW VC RP 2.2µF 4.7µH 33nF –+ + gm = 1000µA/V VOL TAGE REGULATION AMPLIFIER 4.7µF VOUT – 10V REGULATOR ISMON ISN ISP 100k 549k 12.1k FB FAUL T INTVCC 0.1/uni03BCF 0.1/uni03BCF

Rev. 0 For more information www.analog.com OPERATION The LT8386 is a Silent Switcher step-up LED driver that utilizes fixed-frequency peak current control to accurately regulate the current through a string of LEDs. It includes two power switches, their drivers, and a diode for provid- ing power to the top switch driver . The switches connect the external inductor terminal connected to the SW pin alternately to the ground and then to the output (V OUT). The inductor current rises and falls accordingly and the peak current can be regulated by adjusting the duty ratio of the power switches through the combined effect of the other circuit blocks. The synchronous controller ensures the power switches do not conduct at the same time, and a programmable oscillator turns on the bottom switch at the beginning of each switching cycle. The frequency of this oscillator is set by an external resistor at the RT pin and can be overrid - den by external pulses at the SYNC/SPRD pin. The SYNC/ SPRD pin can also be used to command spread spectrum frequency modulation (SSFM), which reduces radiated and conducted electromagnetic interference (EMI). The bottom switch is turned off by the peak current com- parator which waits during the on-time for the increasing inductor current to exceed the target set by the voltage at the V C pin. This target is modified by a signal from the oscillator which stabilizes the inductor current. A network of passive components at the VC pin is necessary to sta- bilize this regulation loop. The target for the inductor current is derived from the desired LED current programmed by the voltage at the CTRL pin. The analog-or-digital detector and the control buffer convert either a DC voltage or duty cycle of pulses at the CTRL pin into the input for the current regulation amplifier . The other input to this amplifier comes from the ISP and ISN pin voltages. An external current sense resis- tor between these pins should be placed in series with the string of LEDs such that the voltage across it provides the feedback to regulate the LED current. The current regula- tion amplifier then compares the actual LED current to the desired LED current and adjusts VC as necessary. The voltage regulation amplifier overrides the current reg- ulation amplifier when the FB pin voltage is higher than an internal 1.2V reference. An external resistor network from the LED string to the FB pin provides an indication of the LED string voltage and allows the voltage amplifier to prevent overvoltage of the LED string. The ISP , ISN, and FB pin voltages are also monitored to detect fault conditions like open and short circuits, which are then reported by pulling FAUL T pin low. The response to a fault can be selected either to try hiccup restarts or to latchoff by the choice of an external resistor connected to the SS pin. Refer to the Applications Information section for a detailed explanation of fault responses. Finally, pulse-width modulation (PWM) of the LED current is achieved by turning on and off an external PMOS switch between the V OUT and the string of LEDs. An external pulse at the PWM pin controls the state of the PWM driver or a DC voltage at the PWM pin dictates the duty ratio of an internal PWM pulse, whose frequency is programmed with an external resistor at the RP pin. After each pulse, when the PMOS switch opens, the LT8386 controls the voltages of the capacitors at VC and VOUT to ensure a rapid recovery for the next pulse.

requirements of an application. current sense resistor is used. greater than 1.6V. The low level must be less than 0.4V. the duty ratio of the pulse as shown in Figure 2. Figure 1. Analog CTRL Range

8386 F01

Figure 2. Duty Cycle CTRL Range

8386 F02

Figure 3. Setting CTRL with NTC Resistors

8386 F03

cies from 2MHz down to 200kHz as shown in Table 1. but increase switching power losses and radiated EMI. Table 1. RT Resistance Range nor SSFM is required, connect SYNC/SPRD to GND. mum duty cycle is 93% at 2MHz switching frequency. Figure 4. Typical Conducted Peak EMI of the LT8386

8386 F04

switch current limit over VIN pin voltages. assuming 90% efficiency for the given conditions. an inductor with low core loss and low DC resistance. are recommended sources of inductors. Table 2. Inductor Manufacturers types over wide voltage and temperature ranges. Figure 5. Adaptive Peak Switch Current Limit age, over the duty cycle without subharmonic oscillations.

8386 F05

Table 3. Capacitor Manufacturers Note 76 for more information. capacitors in parallel is an effective way to reduce ESR. tor types over wide voltage and temperature ranges. VOUT capacitor placement for the LQFN package. Figure 6. Placement of Output Capacitors

8386 F06

other grounded chassis systems.

the current sense resistor , and connect PWM to INTVCC. should be greater than the maximum output voltage. to or greater than the output voltage. Table 4. PMOS Manufacturers Table 5. Internal PWM Dimming Frequencies

Figure 7. When V ming ratio is 100% and the PWMTG switch will stay on. Figure 7. The Internal PWM Mapping of the LT8386

512 STEPS VPWM

8386 F07

512 STEPS

Figure 8. ISMON Filter Configuration

8386 F08

both internal and external PWM operations. Figure 9. FB Resistor Configuration

8386 F09

10k resistor would limit the ripple on ISMON to 1%.

pin exceeds the 1.266V FB overvoltage lockout threshold. than 60V when the FB voltage is 1.266V. Figure 10. FAUL T Resistor Configuration

8386 F10

when the LEDs are conducting a large current. other parts to be connected and share a single resistor. held low until the part successfully restarts.

drive the LED at the commanded current level.

8386 F12

Figure 12. Fault Responses: (a) Latchoff and (b) Hiccup Figure 11. SS Capacitor and Resistor Configuration

8386 F11

operating range of the VIN voltage. old can be accurately set by an external resistor divider . threshold and the rising hysteresis voltages in LT8386.

8386 F13

voltage is below the threshold. their connections should be made on that layer. connection for all of the other components separate. the second layer dissipates heat, but also reduces noise. LT8386 for more information. Figure 14. OVLO Threshold and Hysteresis Voltages

8386 F14

Figure 15. EN/UVLO — OVLO Threshold and Hysteresis Voltages

8386 F15

single resistor string consisting of three series resistors. hysteresis voltages for EN/UVLO and OVLO. used. Do not leave these pins open.

Rev. 0 For more information www.analog.com TYPICAL APPLICATIONS 2MHz, 300mA Boost LED Driver Using External PWM Dimming 200ns PWM On/ 1Hz fPWM (5,000,000:1) 33nF L T8386

8386 TA02a

L1, 4.7µH FB VOUT GND ISP ISN PWMTG ISMON EN/UVLO OVLO VREF CTRL PWM SYNC/SPRD INTVCC FAUL T SW BST 499k 140k VC 100nF 100k 4.7nF 4.7µF 50V 333m/uni03A9 VIN 12V 45.3k 2MHz f SW 48V 300mA LED 10k 549k 10µF 100V 12.1k 100k PIN NOT USED IN THIS CIRCUIT : BST L1: COILCRAFT XEL4030-472MEC M1: VISHAY SQ2309ES 28k 1µF 2.2µF 0.1µF 100V 20µs PWM On/ 1Hz fPWM (50,000:1) 200ns PWM On/ 100Hz f PWM (50,000:1) 200ns (DIV) ILED 100mA/DIV VPWM 2V/DIV

8386 TA02b

200ns (DIV) ILED 100mA/DIV VPWM 2V/DIV

8386 TA02c

200ns (DIV) ILED 100mA/DIV VPWM 2V/DIV

8386 TA02d

20/uni03BCs (DIV) ILED 100mA/DIV VPWM 2V/DIV

8386 TA02e

20/uni03BCs (DIV) ILED 100mA/DIV VPWM 2V/DIV

8386 TA02f

20/uni03BCs (DIV) ILED 100mA/DIV VPWM 2V/DIV

8386 TA02g

20µs PWM On/ 100Hz f PWM (500:1) 200ns PWM On/ 1kHz f PWM (5,000:1) 20µs PWM On/ 1kHz f PWM (50:1)

Rev. 0For more information www.analog.com TYPICAL APPLICATIONS 2MHz, 300mA Boost LED Driver Using Internal PWM Dimming 1µF 33nF L T8386

8386 TA03a

L1, 4.7µH FB VOUT GND ISP ISN PWMTG ISMON EN/UVLO OVLO VREF CTRL PWM SYNC/SPRD INTVCC FAUL T SW BST 499k 140k VC 100nF 100k 4.7nF 4.7µF 50V 333m/uni03A9 VIN 12V 45.3k 2MHz f SW 48V 300mA LED 10k 549k 10µF 100V 12.1k 100k PIN NOT USED IN THIS CIRCUIT : BST L1: COILCRAFT XEL4030-472MEC M1: VISHAY SQ2309ES 28k VPWM 332k 122Hz f PWM 0.1µF 100V 2.2µF 5/uni03BCs (DIV) ILED 100mA/DIV

8386 TA03b

VPWM = 1.003V 20/uni03BCs (DIV) ILED 100mA/DIV VPWM 500mV/DIV

8386 TA03c

VPWM = 250V TO 350mV NOISY SIGNAL 512:1 Internal PWM Dimming Preset PWM Dimming Ratio 1 (100:1)

Rev. 0 For more information www.analog.com TYPICAL APPLICATIONS 400kHz, 94% Efficient 9W (18V, 500mA) Buck-Boost Mode LED Driver 100% PWM DUTY CYCLE V LED = 18V f SW = 400kHz V IN (V) 100 EFFICIENCY (%)

8386 TA04b

5,000:1 External PWM Dimming, 200Hz VIN VIN 6V TO 24V EN/UVLO OVLO INTVCC FAUL T BSTSW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON

8386 TA04a

14.7k 1µF 50V 10nF 22µH 0.2/uni03A9 C11 0.1µF 50V C10 0.1µF 50V 18V 500mA LED SS 249k 400kHz 10nF L1: WURTH 7847709220 M1: VISHAY SQ2309ES Q1: ZETEX FMMT591TA SYNC/SPRD VREF PWM CTRL 100k 10µF 50V 33µF 50V 26.1k 249k 20k R5 20k 10µF , 3×, 50V C12 10µF 50V 1µF 2.2µF 33nF I LED V IN = 12V f PWM = 200Hz 200ns/DIV

8386 TA04c

V ILED 200mA/DIV VLED 2V/DIV

Rev. 0For more information www.analog.com PACKAGE DESCRIPTION Information furnished by Analog Devices is believed to be accurate and reliable. However , no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 28 (26)-Lead (4mm × 5mm × 0.95mm) (Reference L TC DWG # 05-08-1486 Rev Ø) DETAIL B A PACKAGE TOP VIEW PIN 1 CORNER Y X aaa Z2× PACKAGE BOTTOM VIEW SEE NOTES E D b 0.375 e e b 0.35 0.35 LQFN 28(26) 0919 REV Ø TRAY PIN 1 BEVEL PACKAGE IN TRAY LOADING ORIENTATION COMPONENT PIN 1 DETAIL B SUBSTRATE MOLD CAP // bbb Z Z DETAIL A DETAIL C SUGGESTED PCB LAYOUT TOP VIEW 0.0000 0.0000 0.2500 0.2500 0.7500 0.7500 1.2500 1.2500 1.7500 1.7500 1.2500 0.7500 0.2500 0.2500 1.2500 0.7500 PIN 1 NOTCH 0.20 × 45° 23 28 14 9 aaa Z 2× M X Y Z ccc MXY Z ccc 1.65 1.65 1.15 1.15 0.25 ±0.05 0.70 ±0.05 5.50 ±0.05 4.50 ±0.05 ddd Z 26× 26b e SYMBOL A L b D E e aaa bbb ccc ddd eee fff MIN 0.85 0.30 0.22 NOM 0.95 0.40 0.25 4.00 5.00 2.50 3.50 0.50

0.25 REF

0.70 REF

1.05 0.03 0.50 0.28 0.10 0.10 0.10 0.10 0.15 0.08 NOTES SUBSTRATE THK MOLD CAP HT DIMENSIONS Z DETAIL C DETAIL A NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 2. ALL DIMENSIONS ARE IN MILLIMETERS 3. PRIMARY DATUM -Z- IS SEATING PLANE METAL FEATURES UNDER THE SOLDER MASK OPENING NOT SHOWN SO AS NOT TO OBSCURE THESE TERMINALS AND HEAT FEATURES DETAILS OF PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PIN 1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE

6 THE EXPOSED HEAT FEATURE MAY HAVE OPTIONAL CORNER RADII

7 CORNER SUPPORT PAD CHAMFER IS OPTIONAL

L e/2 PACKAGE OUTLINE 0.375 0.20 0.375

Rev. 0 For more information www.analog.com www.analog.com  ANALOG DEVICES, INC. 2021 RELATED PARTS TYPICAL APPLICATION PART NUMBER DESCRIPTION COMMENTS LT3922/3922-1 36V, 2A Synchronous Step-Up LED Driver with 25,000:1 Dimming VIN = 2.8V to 36V, VOUT(MAX) = 40V, 128:1 Internal Dimming and 25,000:1 External Dimming, 4mm x 5mm QFN-28 LT3932/3932-1 36V, 2A Synchronous Step-Down LED Driver V IN = 3.6V to 36V, VOUT = 0V to 36V, 128:1 Internal Dimming and 5,000:1/10,000+:1 External Dimming, 4mm x 5mm QFN-28 LT3942 36V, 2A Synchronous Buck-Boost Converter and LED Driver VIN = 3V to 36V, VOUT = 0V to 36V, 128:1 Internal Dimming and 5,000:1 External Dimming, 4mm x 5mm QFN-28 CISPR25 Conducted EMI Performance Current Method CISPR25 Conducted EMI Performance Current Method Low EMI 330kHz, 45V to 500mA Boost LED Driver with SSFM L T8386

8386 TA05a

L1, 22µH FB VOUT GND ISP ISN PWMTG ISMON EN/UVLO OVLO VREF CTRL PWM SYNC/SPRD INTVCC FAUL T SW BST 499k 232k VC 100nF 1nF 0.2/uni03A9 294k 330kHz f SW 10k 22.1k 51k FB1, FB2: FBMH3225HM601NTV M1: VISHAY SQ2309ES L1: COILCRAFT XAL6060-223ME FB3: FBMH2012HM221-TV L2: COILCRAFT XAL5050-103ME 19.6k 1µF 50V 2.2µF 50V 4.7µF 100V 0.1µF 100V NEAR IC 0.1µF 50V V IN 12V FB1 L2, 10µH FB2 10nF 100V 45V 500mA LED FB3 2.2/uni03BCF 0.1µF 1µF 0.1µF CLASS 5 PEAK LIMIT L T8386 DC3008A Ambient FREQUENCY (MHz) 0.1 100 300 –40 –30 –20 –10 PEAK CE (dBµA) 50MM

8386 TA05b

FREQUENCY (MHz) 0.1 100 300 –40 –30 –20 –10 PEAK CE (dBµA) 750MM

8386 TA05c