LT3932 LINER
Document overview
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Technical content
For more information www.linear .com/L T3932 TYPICAL APPLICATION FEATURES DESCRIPTION 36V, 2A Synchronous Step-Down LED Driver The LT®3932 is a monolithic, synchronous, step-down DC/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 the duty cycle of pulses at the CTRL pin. An output volt- age limit can be set with a resistor divider to the FB pin. The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT3932 also includes a driver for an external, high side PMOS for PWM dimming and an internal PWM signal generator for analog control of PWM dimming when an external signal is not available. The LT3932-1 permits higher dimming ratios. Additional features include an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault report- ing for open-circuit and short-circuit load conditions, and thermal shutdown. 2A LED Driver with Internal PWM Dimming Internal PWM Dimming
APPLICATIONS
n±1.5% LED Current Regulation n±1.2% Output Voltage Regulation n5000:1/10000+:1 PWM Dimming at 100Hz (L T3932/L T3932-1) n128:1 Internal PWM Dimming nSpread-Spectrum Frequency Modulation nSilent Switcher® Architecture for Low EMI n3.6V to 36V Input Voltage Range n0V to 36V LED String Voltage n200kHz to 2MHz with SYNC Function n99.9% Maximum Duty Cycle nAnalog or Duty Cycle LED Current Control nOpen/Short LED Protection and Fault Indication nAccurate LED Current Sense with Monitor Output nProgrammable UVLO nThermally Enhanced 28-Pin (4mm u 5mm) QFN nAutomotive Lighting nIndustrial and General Purpose Lighting nMachine Vision Systems All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents including 7199560, 7321203, 9596728, 9642200 and other patents pending. 30.1k 274k 45.3k 110k 10k 50m/uni03A9 22nF INTVCC 2.2µF 2.2µF 100nF 10nF
3932 TA01a
2x1µF 8.2µH 28.7k 162k 100k 100k 100k 10µF COUT 100µF VIN EN/UVLO VREF CTRL PWM SYNC/SPRD INTVCC SS RT RP VC ISP ISN FB VOUT SW BST L T3932 PWMTG VIN 12V VOUT 9V 1A 2MHz ISMONFAUL TFAUL T ISMON 7.8kHz GND PWM = 1.078V (8% PWM DUTY RATIO) 2µs/DIV SW 20V/DIV PWMTG 10V/DIV IL 1A/DIV ILED 1A/DIV
3932 TA01b
For more information www.linear .com/L T3932 PIN CONFIGURATIONABSOLUTE MAXIMUM RATINGS SW, BST, INTVCC, VREF, ISMON, PWMTG, RT, Operating Junction Temperature Range (Notes 3, 4) (Note 1) 9 10 TOP VIEW UFD PACKAGE 28-LEAD (4mm × 5mm) PLASTIC QFN 11 12 13 28 27 26 25 24 1VREF SS VC FB ISP ISN ISMON FAUL T GND VIN VIN SW SW V IN VIN GND CTRL EN/UVLO V IN INTVCC BST GND RP RT SYNC/SPRD PWM PWMTG VOUT 8 15 GND TJA = 25°C/W (MEASURED ON DC2286A) EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 5V unless otherwise noted. LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3932EUFD#PBF LT3932EUFD#TRPBF 3932 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C LT3932IUFD#PBF LT3932IUFD#TRPBF 3932 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C LT3932HUFD#PBF LT3932HUFD#TRPBF 3932 28-Lead (4mm × 5mm) Plastic QFN –40°C to 150°C LT3932EUFD-1#PBF LT3932EUFD-1#TRPBF 39321 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C LT3932IUFD-1#PBF LT3932IUFD-1#TRPBF 39321 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C LT3932HUFD-1#PBF LT3932HUFD-1#TRPBF 39321 28-Lead (4mm × 5mm) Plastic QFN –40°C to 150°C Consult ADI 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/. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. PARAMETER CONDITIONS MIN TYP MAX UNITS Input Voltage Range 3.6 36 V VIN Pin Quiescent Current EN/UVLO = 2V, Not Switching EN/UVLO = 300mV, Shutdown l 2.2 2.7 mA µA EN/UVLO Threshold (Falling) 1.09 1.15 1.21 V EN/UVLO Rising Hysteresis 20 mV EN/UVLO Pin Hysteresis Current 4 µA http://www.linear.com/product/LT3932#orderinfo
For more information www.linear .com/L T3932
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS Reference VREF Voltage IVREF = 0µA IVREF = 500µA l 1.975 1.980 1.998 2.020 2.016 V V V REF Pin Current Limit VREF = 1.9V, Current Out of Pin 2 mA LED Current Regulation CTRL-Off Threshold (Falling) l 200 218 228 mV CTRL-Off Rising Hysteresis 20 mV CTRL Pin Current VCTRL = 2V −100 100 nA Sense Voltage (VISP−VISN) (Analog Input) VCTRL = 1.5V (100%), VIN = 36V, VISP = 24V VCTRL = 750mV (50%), VIN = 36V, VISP = 24V VCTRL = 300mV (5%), VIN = 36V, VISP = 24V l l l 98.5 48.5 100 101.5 51.5 mV mV mV ISP Pin Current V IN = 36V, VISP = 24V, VCTRL = 2V, Current Into Pin 50 µA ISN Pin Current VIN = 36V, VISN = 23.9V, VCTRL = 2V, Current Into Pin 50 µA ISP/ISN Common Mode Range VIN = 36V (Note 5) 0 36 V Current Error Amplifier T ransconductance V IN = 36V, VISP = 24V 200 µA/V Duty Cycle Control of LED Current Sense Voltage (VISP−VISN) (Duty Cycle Input) CTRL Duty = 75% (100%), VIN = 36V, VISP = 24V CTRL Duty = 37.5% (50%), VIN = 36V, VISP = 24V CTRL Duty = 15% (5%), VIN = 36V, VISP = 24V 100 101 mV mV mV CTRL Pulse Input High (V IH) 1.6 V CTRL Pulse Input Low (VIL) 0.4 V CTRL Pulse Input Frequency Range 100 1000 kHz Voltage Regulation FB Regulation Voltage VISP = VISN = 6V, VCTRL = 2V l 0.988 1.000 1.012 V FB Pin Current VFB = 1V −100 100 nA Voltage Error Amplifier T ransconductance 480 µA/V Power Stage Peak Current Limit 3.0 3.6 4.2 A Minimum Off-Time (Note 6) 55 ns Minimum On-Time (Note 6) 55 ns Bottom Switch On-Resistance 90 m/uni03A9 Top Switch On-Resistance 90 m/uni03A9 Oscillator Programmed Switching Frequency (f SW) R T = 45.3k, VSYNC/SPRD = 0V RT = 523k, VSYNC/SPRD = 0V l l 1900 180 2000 200 2100 230 kHz kHz Spread Spectrum Frequency Range RT = 45.3k, VSYNC/SPRD = 3.3V RT = 523k, VSYNC/SPRD = 3.3V 1900 180 2650 290 kHz kHz RT Pin Current Limit V RT = 0V, Current Out of Pin 34 µA SYNC/SPRD Threshold (Rising) 1.4 1.5 V SYNC/SPRD Falling Hysteresis 220 mV SYNC/SPRD Pin Current VSYNC/SPRD = 3.3V −100 100 nA Soft-Start SS Pin Charging Current VSS = 0V 20 µA The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 5V unless otherwise noted.
For more information www.linear .com/L T3932 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 LT3932E 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 LT3932I is guaranteed to meet performance specifications over the −40°C to 125°C operating junction temperature range. The LT3932H is guaranteed over the −40°C to 150°C operating junction temperature range. Operating lifetime is derated for junction temperatures greater than 125°C. 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. Note 5: The current sense error amplifier is tested with V ISP = 36V, and separately, with VISN = 0V. Note 6: The MIN on and off times are guaranteed by design and are not tested. PARAMETER CONDITIONS MIN TYP MAX UNITS SS Pin Discharging Current VSS = 2V 1.25 µA SS Lower Threshold (Falling) 200 mV SS Higher Threshold (Rising) 1.7 V Fault Detection Open-Circuit Threshold (FB Rising) l 930 950 970 mV Open-Circuit Falling Hysteresis 55 mV Short-Circuit Threshold (FB Falling) l 180 200 220 mV Short-Circuit Rising Hysteresis 50 mV FAUL T Pull-Down Current VFAUL T = 200mV, VFB = 0V 100 µA FAUL T Leakage Current VFAUL T = 3.3V, VFB = 700mV −100 100 nA Overvoltage Protection FB Overvoltage Threshold (FB Rising) 1.050 V FB Overvoltage Falling Hysteresis 48 mV LED Current Monitor ISMON Voltage V ISP − VISN = 100mV (100%), VISP = 12V VISP − VISN = 10mV (10%), VISP = 12V 0.965 1.000 100 1.030 120 V mV PWM Driver PWMTG Gate Drive (V OUT – VPWMTG) V OUT = 12V, VPWM = 2V l 10 11 V PWM Threshold (Rising) VOUT = 12V 1.4 V PWM Falling Hysteresis VOUT = 12V 200 mV PWM Pin Current VPWM = 2V −100 100 nA PWM to PWMTG Propagation Delay Turn-On Turn-Off C PWMTG = 2.2nF (Connected from VOUT to PWMTG), VOUT = 12V 100 100 ns ns Analog Control for PWM Dimming PWM Voltage for 100% Dimming R P = 28.7k, VREF = 2V 2.00 V PWM Voltage for 0% Dimming RP = 28.7k, VREF = 2V 0.99 V PWM Dimming Accuracy RP = 28.7k, VREF = 2V, VPWM = 1.1V RP = 28.7k, VREF = 2V, VPWM = 1.9V l l 7.8 12.4 PWM Dimming Frequency R P = 28.7k, RT = 45.3k, VSYNC/SPRD = 0V RP = 332k, RT = 45.3k, VSYNC/SPRD = 0V 7.42 116 7.81 122 8.20 128 kHz Hz RP Pin Current Limit RP = 0V, Current Out of Pin 60 µA The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 5V unless otherwise noted.
For more information www.linear .com/L T3932 TYPICAL PERFORMANCE CHARACTERISTICS VIN Shutdown Current VIN Quiescent Current INTVCC Voltage INTVCC Load Regulation VREF Voltage VREF Load Regulation EN/UVLO Threshold EN/UVLO Pin Current VIN UVLO Threshold VIN = 12V, unless otherwise noted. TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 1.1 1.2 1.3 1.4 1.5 1.6EN/UVLO VOL TAGE (V)
3932 G01
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 3.7 4.0 4.3 4.6 4.9 5.2 5.5 5.8 6.1EN/UVLO CURRENT (µA)
3932 G02
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 2.4 2.6 2.8 3.0 3.2 3.4 3.6VIN VOL TAGE (V)
3932 G03
VEN/UVLO = 0.3V TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 0.01 0.1 100 10k VIN CURRENT (nA)
3932 G04
VEN/UVLO = 1V TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0VIN CURRENT (mA)
3932 G05
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5INTVCC VOL TAGE (V)
3932 G06
INTVCC CURRENT (mA) 0 3 6 9 12 15 3.28 3.30 3.32 3.34 3.36 3.38 3.40INTVCC VOL TAGE (V)
3932 G07
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 1.97 1.98 1.99 2.00 2.01 2.02 2.03VREF VOL TAGE (V)
3932 G08
VREF CURRENT (mA) 0 0.4 0.8 1.2 1.6 2 1.97 1.98 1.99 2.00 2.01 2.02 2.03VREF VOL TAGE (V)
3932 G09
For more information www.linear .com/L T3932 TYPICAL PERFORMANCE CHARACTERISTICS RP and RT Pin Current Limit SS Pin Pull-Up Current SS Thresholds SW Frequency Internal PWM Frequency PWM Duty Ratio VREF Line Regulation INTVCC and VREF UVLO Threshold Minimum On-Time and Off-Time VIN VOL TAGE (V) 0 6 12 18 24 30 36 1.97 1.98 1.99 2.00 2.01 2.02 2.03VREF VOL TAGE (V)
3932 G10
25°C 150°C –50°C INTVCC VREF TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3VOL TAGE (V)
3932 G11
MINIMUM OFF–TIME MINIMUM ON–TIME TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 75TIME (ns)
3932 G12
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 70CURRENT (µA)
3932 G13
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 24SS CURRENT (µA)
3932 G14
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 0.4 0.8 1.2 1.6 2.0SS VOL TAGE (V)
3932 G15
RT = 45.3k RT = 523k TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 1400 1600 1800 2000 2200 180 200 220 240 260 SW FREQUENCY (kHz)
3932 G16
RT = 45.3k EXTERNAL PWM RP RESISTANCE (/uni03A9) 10k 100k 1M 0.1 10PWM FREQUENCY (kHz)
3932 G17
PWM VOL TAGE (V) 0 0.5 1 1.5 2 2.5 3 –10 100 110DUY RATIO (%)
3932 G18
VIN = 12V, unless otherwise noted.
For more information www.linear .com/L T3932 TYPICAL PERFORMANCE CHARACTERISTICS LED Current (100% Regulation) LED Current (5% Regulation) ISMON Voltage Peak SW Current Limit LED Current Line Regulation LED Current vs VOUT LED Current (Analog CTRL) LED Current (Digital CTRL) LED Voltage Limit CTRL VOL TAGE (V) –10 100 110VISP - VISN (mV)
3932 G19
CTRL DUTY RATIO (%) 0 12.5 25 37.5 50 62.5 75 87.5 100 –10 100 110VISP - VISN (mV)
3932 G20
VCTRL = 2V FB VOL TAGE (V) 100 125VISP – VISN (mV)
3932 G21
VCTRL = 1.5V
300 UNITS155°C
25°C –50°C VISP - VISN (mV) 120 150 180 210 240 270 300NUMBER OF UNITS
3932 G22
VCTRL = 300mV 25°C –50°C VISP - VISN (mV) 120 150 180 210 240 270 300NUMBER OF UNITS
3932 G23
VISP – VISN (mV) 0 50 100 150 200 250 300 0.5 1.0 1.5 2.0ISMON VOL TAGE (V)
3932 G24
DUTY RATIO (%) 10 30 50 70 90 2.0 2.4 2.8 3.2 3.6 4.0PEAK SW CURRENT (A)
3932 G25
2 LEDs (APPROX. 6V) 2MHz SW FREQUENCY VIN VOL TAGE (V) 0 6 12 18 24 30 36 48.0 48.4 48.8 49.2 49.6 50.0VISP - VISN (mV)
3932 G26
VCTRL = 735mV 2MHz SW FREQUENCY VCTRL = 750mV VIN = 36V VOUT VOL TAGE (V) 0 6 12 18 24 30 36 49.0 49.4 49.8 50.2 50.6 51.0VISP - VISN (mV)
3932 G27
VIN = 12V, unless otherwise noted.
For more information www.linear .com/L T3932 TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs VIN Efficiency vs ILED Regulated FB Voltage PWMTG Voltage PWM Driver Propagation Delay FB OVLO Threshold FB OPENLED Threshold FB SHORTLED Threshold Power Switch On-Resistance VIN = 12V, unless otherwise noted. RISING FALLING TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 0.80 0.85 0.90 0.95 1.00 1.05 1.10FB VOL TAGE (V)
3932 G28
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 0.10 0.15 0.20 0.25 0.30 0.35 0.40FB VOL TAGE (V)
3932 G29
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 100 150 200 250 300RESISTANCE (mOhm)
3932 G30
2 LEDs (APPROX. 6V , 1A) 400kHz 2MHz VIN VOL TAGE (V) 5 10 15 20 25 30 35 40 100EFFICIENCY (%)
3932 G31
VIN = 24V 2MHz SW FREQUENCY 5 LEDs (APPROX. 15V) 4 LEDs (APPROX. 12V) ILED (mA) 0 400 800 1200 1600 2000 100EFFICIENCY (%)
3932 G32
VCTRL = 2V VISP – VISN = 0V TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 0.97 0.98 0.99 1.00 1.01 1.02FB VOL TAGE (V)
3932 G33
VOUT = 20V VPWM = 2V TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 12VOUT – VPWMTG (V)
3932 G34
CPWMTG = 2.2nF (X7R) DATA INCLUDES CAPACITANCE VARIATION WITH TEMPERATURE TURN–ON TURN–OFF TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 100 125 150 175 200 225 250PROPAGATION DELAY (ns)
3932 G35
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 0.900 0.950 1.000 1.050 1.100FB VOL TAGE (V)
3932 G36
For more information www.linear .com/L T3932 TYPICAL PERFORMANCE CHARACTERISTICS Internal PWM Duty Ratio (90%) Input Voltage T ransient Response Input Voltage T ransient Response Turn-On and Turn-Off Start-Up with 10% Internal PWM Start-Up with 90% Internal PWM C/10 Threshold DA Current Limit Internal PWM Duty Ratio (10%) VIN = 12V, unless otherwise noted. RISING FALLING TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 18VISP - VISN (mV)
3932 G37
TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 150 2.0 2.1 2.2 2.3 2.4 2.5SW CURRENT (A)
3932 G38
VPWM = 1.1V
250 UNITS150°C
25°C –50°C PWM DUTY RATIO (%) 120 160 200NUMBER OF UNITS
3932 G39
VPWM = 1.9V 25°C –50°C PWM DUTY RATIO (%) 120 160 200NUMBER OF UNITS
3932 G40
15V TO 25V INPUT VOL TAGE STEP 3 LEDs (APPROX. 9V) 1ms/DIV VIN 10V/DIV ILED 100mA/DIV
3932 G41
25V TO 15V INPUT VOL TAGE STEP 3 LEDs (APPROX. 9V) 1ms/DIV VIN 10V/DIV ILED 100mA/DIV
3932 G42
3 LEDs (APPROX. 9V) 5ms/DIV VIN 20V/DIV VOUT 5V/DIV ILED 500mA/DIV
3932 G43
FRONT PAGE APPLICATION WITH PWM = 1.1V 3 LEDs (APPROX. 9V) 5ms/DIV VIN 20V/DIV VOUT 5V/DIV ILED 500mA/DIV
3932 G44
FRONT PAGE APPLICATION WITH PWM = 1.9V 3 LEDs (APPROX. 9V) 5ms/DIV VIN 20V/DIV VOUT 5V/DIV ILED 500mA/DIV
3932 G45
For more information www.linear .com/L T3932 PIN FUNCTIONS VIN: Input Voltage Pins. These pins supply power to the internal, high performance analog circuitry, and they sup- ply the inductor current when the internal high side power switch is on. Connect capacitors between these pins and GND and see Selecting and Placing the Input Capacitors in Applications Information for advice regarding their placement. EN/UVLO: Enable and Undervoltage Lockout Pin. A voltage at this pin greater than 1.15V will enable switching, and a voltage less than 300mV is guaranteed to shut down the internal current bias and sub-regulators. A resistor network between this pin and GND can be used to set the pin voltage and automatically lockout the part when V IN is below a certain level. No internal components 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. INTVCC: 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, but bypass it with a 2.2µF capacitor to GND. ISP: 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. ISN: 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. ISMON: Output Current Monitoring Pin. This pin provides a buffered voltage output equal to 10mV for every 1mV between ISP and ISN. CTRL: 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 current supplied to the load). Alternatively, a digital pulse at this pin with duty cycle 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 Regulated LED Current in Typical Performance Curves and Programming LED Current with the CTRL Pin in Ap- plications Information. V REF: Reference Voltage Pin. This pin provides a buffered 2V reference capable of 2mA drive. It can be used to sup- ply resistor networks for setting the voltages at the CTRL and PWM pins. Bypass with a 2.2/uni03BCF capacitor to GND. FB: Feedback Pin. When the voltage at this pin is near 1V, 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 1.05V, an overvoltage lockout comparator disables switching. FAUL T: Fault Pin. Connect to INTV CC through a resistance of 100k. When the FB pin voltage is less than 200mV, an internal switch pulls this pin low to indicate a short-circuit. When FB is greater than 950mV and the voltage between ISP and ISN is simultaneously less than 10mV, the switch pulls this pin low to indicate an open-circuit. SS: Soft-Start Pin. At startup and recovery from fault conditions, a 20/uni03BCA 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. A resistor from SS to INTV CC is used to select one of several fault modes. See Soft-Start and Fault Modes in Applications Information for more details. V C: Compensation Pin. A capacitor connected from this pin to GND stabilizes the current and voltage regulation. See Stabilizing the Regulation Loop in the Applications Information section for more details. SW: Switch Pins. These two pins are internally connected to the power devices and drivers. They should always be tied together. In normal operation, the voltage of these pins will switch between the input voltage and zero at the programmed frequency. Do not force any voltage on these pins. RT: Timing Resistor Pin. A resistor from this pin to GND programs the switching frequency between 200kHz and 2MHz. Do not leave this pin open.
For more information www.linear .com/L T3932 PIN FUNCTIONS SYNC/SPRD: Synchronization Pin. To override the pro - grammed 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. BST: Boost Pin. This pin supplies the high side power switch driver. Connect a 22nF capacitor between this pin and SW, and connect a diode from INTV CC to BST to charge the capacitor when the SW pin is low. PWM: 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 ratio between 0% and 100%. In this case, place a 1µF bypass capacitor between this pin and GND. Tie this pin high when PWM dimming is not required. PWMTG: PWM Driver Output Pin. This pin can drive the gate of an external, high side PMOS device for PWM dimming of LEDs. Do not force any voltage on this pin. RP: 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 1M/uni03A9. If using an external PWM pulse for LED dimming, tie this pin to GND. V OUT: PWM Driver Supply Pin. This pin supplies an internal regulator for the driver of the external PMOS device. Tie this pin to the output voltage even if dimming is not required. GND: Ground Pins. These must be soldered to the ground plane of the circuit board.
For more information www.linear .com/L T3932 BLOCK DIAGRAM 25 1624 17 20 21 INTERNAL VCC REGULATOR AND UVLO 2V REFERENCE SYNCHRONOUS CONTROLLER S R Q EN/UVLO VIN CIN CVCC REN1 RT REN2 CREF INTVCC BST BOTTOM SWITCH DRIVER TOP SWITCH DRIVER 50m/uni03A9 4.7µF 8.2µH VIN VIN SW DA CURRENT LIMIT VREF SYNC/SPRD CTRL 200kHz TO 2MHz OSCILLATOR VOUT 22nF CIN ISN 3923 BD ISP FB RT SSGND VC CSS CC RSS RP 200mV 950mV 1.4V 1.0V 20µA 1.25µA 3k3k VOUT – 10V REGULATOR INTERNAL PWM SIGNAL FAUL T LOGICFAUL T COMPARATORS FAUL T LOGIC CURRENT REGULATION AMPLIFIER gm = 200µS VOL TAGE REGULATION AMPLIFIER gm = 480µS PEAK CURRENT COMPARATOR 1.25V 250mV PWMTG DRIVER PWM PWMTG ISMON 10x FAUL T INTVCC RFB1 RFAUL T RFB2 CONTROL BUFFER 30k A/D DETECTOR 22 23 29 INTVCC S/HS/H
For more information www.linear .com/L T3932 OPERATION The LT3932 is a step-down LED driver that utilizes fixed- frequency, peak-current control to accurately regulate the current through a string of LEDs. It includes two power switches and their drivers. The switches connect an external inductor at the SW pin alternately to the input supply and then to ground. 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 top 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 overridden 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 top switch is turned off by the peak current comparator 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 capacitor at the V C pin is necessary to stabilize 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-to-digital detector and the control buffer convert either a DC voltage or digital pulses at the CTRL pin into the input for the current regulation ampli - fier. The other input to this amplifier comes from the ISP and ISN pin voltages. An external current sense resistor 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 programmed LED current and adjusts V C as necessary. The voltage regulation amplifier overrides the current regulation amplifier, when the FB pin voltage approaches an internal 1V 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 FB voltage is also monitored to detect fault conditions like open and short-circuits, which are then reported by pulling the FAUL T pin low. The response to a fault can be selected either to try hiccup restarts or to latch-off by the choice of an external resistor connected to the SS pin. Refer to Applications Information for a detailed explana- tion of fault responses. Finally, pulse-width-modulation (PWM ) of the LED cur - rent is achieved by turning on and off an external PMOS switch between the inductor 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 by an external resistor at the RP pin. After each pulse, when the PMOS switch is open, the LT3932 preserves the voltages of the capacitors at V C and VOUT to ensure a rapid recovery for the next pulse.
vary with the duty ratio of the pulse as shown in Figure 2. Figure 1. Analog CTRL Range Figure 2. Duty Ratio CTRL Range Figure 3. Setting CTRL with NTC Resistors requirements of an application. the LED string when a 50m/uni03A9 current sense resistor is used.
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Figure 4. Typical Average Conducted Emissions increase switching power losses and radiated EMI. Table 1. RT Resistance Range should correspond to the frequency of the external clock. T resistor to set the frequency. SSFM is required, connect SYNC/SPRD to GND. various standard industrial tests related to interference. switching period regardless of the state of the CTRL pin. is off, the current is sensed through the low-side switch. inductor current reaches equilibrium as shown in Figure 5.
3932 F04
in regulation even at the highest switching frequency.
- VIN(MAX) – VOUT 1V •1MHz fSW However, for high output voltages even the above equation would suggest an inductance value that is too small. For stability, the LT3932 requires an inductance greater than: L = 1 µH •VOUT 1V •1MHz fSW Choose the larger of the values given by these equations. The manufacturers featured in Table 2 are recommended sources of inductors.
Table 2. Inductor Manufacturers
- 1MHz fSW However, applications may still be stable with more or less capacitance, and more capacitance may improve LED current waveforms for large PWM dimming ratios. Use X7R or X5R ceramic capacitors as they retain their capacitance better than other capacitor types over a wide voltage and temperature range. Sources of quality ceramic and electrolytic capacitors are listed in Table 3.
Table 3. Capacitor Manufacturers Figure 5. Extended Off-Time at Current Limit
3932 F05
Figure 6. Placement of Input Capacitors the second layer of the circuit board. applications or other grounded chassis systems. VOUT is below 10V, the gate drive is necessarily reduced. ming may be implemented with the CTRL pin. greater than the output voltage. affected noticeably by gate charging loss or transition loss.
3932 F06
Table 4. PMOS Manufacturers Table 5. Internal PWM Dimming Frequencies capacitor near PWM pin to ground. Figure 7. ISMON Filter Configuration of 10000:1 or greater are possible in some applications.
3932 F07
Figure 8. FB Resistor Configuration Figure 9. FAUL T Resistor Configuration the 1M/uni03A9 resistor would limit the ripple on ISMON to 1%. the output voltage and the FB pin as shown in Figure 8.
3932 F08
3932 F09
It is possible that the FB voltage can exceed the 1V limit. stop switching and resume only when FB decreases to 1V. LEDs are conducting a large current. Figure 9. This configuration allows multiple FAUL T pins determines the maximum output voltage.
shown in Figure 10, will generate a linear ramp voltage. the commanded current level. and the hiccup behavior would therefore be very disruptive. the event of open-circuits and short-circuits. vestigated manually before resuming normal operation. Figure 12. Latch-Off Response to a Fault process will repeat as shown in Figure 11. Figure 11. Hiccup Response to Fault Figure 10. SS Capacitor and Resistor Configuration
3932 F10
3932 F11
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Figure 13. EN/UVLO Resistor Configuration Applications for more details. hysteresis has been added to the 1.15V enable threshold. esis, use 226k and 29.4k for REN2 and REN1, respectively. to be higher than the operational temperature of the part. compromised board design TJA could be 40°C/W or higher.
3932 F13
For more information www.linear .com/L T3932 APPLICATIONS INFORMATION Designing the Printed Circuit Board Note that large switched currents flow through the local input capacitors and the V IN and GND pins. The loops traveled by these currents should be made as small as possible by keeping the capacitors as close as possible to these pins. These capacitors, as well as the inductor, should be placed on the same side of the board as the LT3932 and connected on the same layer. Other large, bulk input capacitors can be safely placed farther from the chip and on the other side of the board. Create a Kelvin ground network by keeping the ground connection for all of the other components separate. It should only join the ground for the input and output capacitors and the return path for the LED current at the exposed pad. There are a few other aspects of the board design that improve performance. An unbroken ground plane on the second layer dissipates heat, but also reduces noise. Likewise minimizing the area of the SW and BST nodes reduces noise. The traces for FB and V C should be kept short to lessen the susceptibility to noise of these high impedance nodes. Matched kelvin connections from the external current sense resistor R S to the ISP and ISN pins are essential for current regulation accuracy. The 2.2/uni03BCF IN- TVCC and VREF capacitors as well as the 22nF BST capacitor should be placed as closely as possible to their respective pins. A capacitor for the CTRL pin and, when the internal dimming feature is used, the PWM pin, can compensate for compromised layouts. Finally, a diode with anode con- nected to ground and cathode to the drain of the PWMTG MOSFET can protect that device from overvoltage caused by excessive inductance in the LED string. Please refer to the demo board layout of the LT3932 for an example of how to implement these recommendations.
For more information www.linear .com/L T3932 TYPICAL APPLICATIONS 2A LED Driver with Duty Cycle LED Current RT 523k 287k RFB2 10k RFB1 RS 50m/uni03A9 LED1 22nF CBST 2×10µF COUT CREF 2.2µF CVCC 2.2µF CSS 100nF CC 10nF CIN2 2×1µF 150µH LED8 RFAUL T 100k CIN1 10µF VIN EN/UVLO VREF CTRL PWM SYNC/SPRD INTVCC SS RT RP VC ISP GND ISN FB VOUT SW BST INTVCC L T3932 PWMTG VIN 36V VOUT 24V , 2A 200kHz L1: WURTH 7447709151 D1: NEXPERIA BAT46WJ M1: VISHAY Si4447ADY RS: OHMITE LVK12R050D COUT1: MURATA GRM32ER71H106K ISMON FAUL TFAUL T ISMON 3.3V 3.3V ENABLE
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Digital CTRL 25% Digital CTRL 50% Digital PWM 25% Digital PWM 50% 500ns/DIV CTRL 5V/DIV PWM 2V/DIV LED CURRENT 1A/DIV
3932 TA02a
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For more information www.linear .com/L T3932 TYPICAL APPLICATIONS 24V Voltage Regulator with Spread Spectrum VINVIN 29V TO 36V CIN1 10µF EN/UVLO L1: COILCRAFT XAL5050-153 RS: OHMITE LVK12R050D COUT: GRM32ER71H106K D1: NEXPERIA BAT46WJ INTVCC FAUL T BST INTVCC SW VOUT FB RP V CRT ISP GND ISN ISMON
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2×1µF CC 10nF CBST 22nF 15µH COUT 2 × 10µF VOUT 24V , 2A MAX REN2 576k REN1 23.7k SS RT 45.3k 2MHz CSS 10nF RSS 1m/uni03A9 CVCC 2.2µF VREF CTRL PWM SYNC/SPRD CREF 2.2µF PWMTG NOT USED Efficiency Load Step Response EFFICIENCY (29VIN) LOSS (29VIN) EFFICIENCY (36VIN) LOSS (36VIN) OUTPUT CURRENT (mA) 0 500 1000 1500 2000 0.5 1.0 1.5 2.0 2.5 3.0 EFFICIENCY (%) ON–CHIP LOSS (W)
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100µs/DIV VOUT 1V/DIV ILOAD 500mA/DIV
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For more information www.linear .com/L T3932 TYPICAL APPLICATIONS REN1 CIN4 1µF REN2 RT 45.3k RC 24.9k RFB2 69.8k RFB1 10k RS 100m/uni03A9 LED1 LED2 CBST 22nF CIN2 4.7µF COUT 4.7µFCREF 2.2µF CVCC 10µF CSS 1nF CC 150pF CB2 100nF CIN5 2x470nF 2.2µH
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33µF VIN EN/UVLO VREF CTRL PWM SYNC/SPRD INTVCC SS RT RP VC ISP ISN FB VOUT SW BST INTVCC L T3932 ISMON, FAUL T NOT USED PWMTG VIN 8V TO 36V VOUT 6V , 1A 2MHz D1: NXP PMEG4010CEJ D1: NEXPERIA BAT46WJ RS: SUSUMU KRL1220D-M-R100-F FB1,2: WURTH 742792040 L1: WURTH 7438323022 M1: VISHAY Si2399DS 50V 1206 50V E LY T. 50V 0603 50V 0402 16V 0805 16V 0402 GND FB2 FB1 232k 39.2k CIN1 2x100nF 50V 0402 DC2286A DEMO BOARD 14V INPUT TO 6V OUTPUT AT 1A CLASS 5 PEAK LIMIT MEASURED EMISSIONS AMBIENT NOISE FREQUENCY (MHz) 0.1 1 10 100 200 –20 –10 AMPLITUDE (dBµV)
3932 TA07a DC2286A DEMO BOARD
14V INPUT TO 6V OUTPUT AT 1A CLASS 5 PEAK LIMIT MEASURED EMISSIONS AMBIENT NOISE FREQUENCY (MHz) 0 100 200 300 400 500 600 700 800 900 1000 –20 –10 AMPLITUDE (dBµV/m)
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14V INPUT TO 6V OUTPUT AT 1A CLASS 5 AVERAGE LIMIT MEASURED EMISSIONS AMBIENT NOISE FREQUENCY (MHz) 0.1 1 10 100 200 –20 –10 AMPLITUDE (dBµV)
3932 TA07c DC2286A DEMO BOARD
14V INPUT TO 6V OUTPUT AT 1A CLASS 5 AVERAGE LIMIT MEASURED EMISSIONS AMBIENT NOISE FREQUENCY (MHz) 0 100 200 300 400 500 600 700 800 900 1000 –20 –10 AMPLITUDE (dBµV/m)
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CISPR25 Peak Conducted Emissions Test CISPR25 Average Conducted Emissions Test CISPR25 Peak Radiated Emissions Test CISPR25 Average Radiated Emissions Test
For more information www.linear .com/L T3932 TYPICAL APPLICATIONS 2A LED Driver with Internal PWM Dimming Internal PWM Dimming Internal PWM Dimming REN1 29.4k REN2 274k RT 45.3k 110k RFB2 10k RFB1 RS 50m/uni03A9 LED1 LED2 22nF CBST CREF 2.2µF CVCC 2.2µF CSS 100nF CC 10nF CIN2 2×1µF 8.2µH RP 28.7k RC 162k LED3
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10µF COUT 100µF VIN EN/UVLO VREF CTRL PWM SYNC/SPRD INTVCC SS RT RP VC ISP ISN FB VOUT SW BST INTVCC L T3932 PWMTG VIN 12V TO 24V VOUT 12V MAX, 2A 2MHz L1: WURTH 74404064082 M1: INFINEON IRF7204 D1: NEXPERIA BAT46WJ RS: OHMITE LVK12R050D COUT: AVX TPME107M020R0035 ISMONFAUL TFAUL T ISMON 7.8kHz GND PWM = 1.078V 2µs/DIV SW 20V/DIV PWMTG 10V/DIV IL 1A/DIV ILED 1A/DIV
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PWM = 1.132V 2µs/DIV SW 20V/DIV PWMTG 10V/DIV IL 1A/DIV ILED 1A/DIV
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For more information www.linear .com/L T3932 TYPICAL APPLICATIONS Multiple String Drivers from Single Boosted 36V Input VINCIN1 10µF EN/UVLOENABLE1 VREF PWM3.3V CTRL L1: WURTH 74404063082 M1: INFINEON IRF7204 R S1: OHMITE LVK12R050D COUT: MURATA GRM32ER714475K D1: NEXPERIA BAT46WJ L0: WÜRTH 7443630420 M0: INFINEON BSZ040N04LS R0: VISHAY WSLP25124L000F D0: ONSEMI MBR1240MFS INTVCC FAUL T BST INTVCC SW VOUT FB RP V CRT ISP GND ISN PWMTG ISMON L T3932 RFB1 110k RFB2 10k RFAUL T 100k CIN2 2×1µF CIN1 10µF CIN2 2×1µF CC 10nF CREF 2.2µF CBST 22nF 8.2µH COUT 4.7µF 12V , 1A MAX RS1 50m/uni03A9 SS RT 45.3k 2MHz CSS 100nF CVCC 2.2µF SYNC/SPRD0V 3.3V RCTRL2 49.9k RCTRL1 30.1k VIN +2 L T3932 (1A EACH) EN/UVLOENABLE2 VREF PWM0V 3.3V CTRL L2: COILCRAFT LPS8045B-153 M2: VISHAY Si2319CDS R S2: OHMITE LVK12R100D COUT: MURATA GRM32ER71H475K D2: NEXPERIA BAT46WJ INTVCC FAUL T BST SW VOUT FB RP V CRT ISP GND ISN PWMTG ISMON
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2.2µF CBST 22nF 15µH COUT 4.7µF 30V , 1A MAX RS2 100m/uni03A9 SS RT 45.3k 2MHz CSS 100nF CVCC 2.2µF SYNC/SPRD0V 3.3V GATE VIN SENSE GND SS SHDN/UVLO SYNC VC RT L T3757 RSHDN2 48.7k RSHDN1 12.1k RC 10k RT 30.9k 400MHz CC 10nF CSS 100nF 4.2µHD0 CIN 10µF VIN 6V MIN FOR OPERATION 10V MIN FOR FULL CURRENT V BUCK 36V , 5A MAX 4m/uni03A9 RFB1 348k RFB2 16.2k INTVCC CVCC 4.7µF COUT 5µF COUT 35µF 50V FBX LED INTVCC
For more information www.linear .com/L T3932 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LT3932#packaging for the most recent package drawings. 28-Lead Plastic QFN (4mm × 5mm) (Reference L TC DWG # 05-08-1712 Rev C) 4.00 ±0.10 (2 SIDES)
2.50 REF
5.00 ±0.10 (2 SIDES) NOTE: 1. DRAWING PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGHD-3). 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT , SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONL Y A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE PIN 1 TOP MARK (NOTE 6) 0.40 ±0.10 27 28 BOTTOM VIEW—EXPOSED PAD
3.50 REF
0.75 ±0.05 R = 0.115 TYP R = 0.05 TYP PIN 1 NOTCH R = 0.20 OR 0.35 × 45° CHAMFER 0.25 ±0.05
0.50 BSC
0.200 REF
0.00 – 0.05 (UFD28) QFN 0816 REV C RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPL Y SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 0.70 ±0.05 0.25 ±0.05 4.10 ±0.05 5.50 ±0.05 2.65 ±0.05 3.10 ±0.05 4.50 ±0.05 PACKAGE OUTLINE 2.65 ±0.10 3.65 ±0.10 3.65 ±0.05 28-Lead Plastic QFN (4mm × 5mm) (Reference LTC DWG # 05-08-1712 Rev C)
For more information www.linear .com/L T3932 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.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER A 02/18 Added LT3932-1 to data sheet. Added 10000:1 PWM dimming ratio for LT3932-1 with supporting text in Features and Description. Added machine vision systems to Applications. Relabeled Soft-Start pin from S to SS. On Figure, added Schottky Diode from INTV CC to BST pin, changed boost capacitor from 100nF to 22nF. Changed TJA from 43°C/W to 25°C/W (based on demo board measurement). Sense voltage VCTRL changed from 2V to 1.5V. ISN pin current VISN value changed from 24V to 23.9V. LED Current and LED Voltage Limit Graphs y-axis corrected to mV units. DA Limit graph retitled to “DA Current Limit”, input step changed from 20V upper limit to 25V on Input Voltage T ransient Response graph. Added additional BST pin description text; corrected BST capacitor value from 100nF to 22nF. DA Current Limit added to Block Diagram. Text added to describe DA Current Limit. Added LT3932-1 text regarding four-cycle limit and machine vision usage. Added text regarding T JA equals 25°C/W using DC2286 demo board, corrected boost capacitor value. Corrected Typical Application figure, reduced VOUT from 30V to 24V, changed digital CTRL 50% graph y-axis from 5A/DIV to 5V/DIV. Add new Efficiency graph. Added Diode D1: Nexperia BAT46WJ. 1, 22, 24, 25, 28 1, 12, 22, 23, 24, 25, 26, 28 22, 24, 25, 26, 28
For more information www.linear .com/L T3932 ¤ANALOG DEVICES, INC. 2018 LT 0218 REV A • PRINTED IN USA www.linear.com/LT3932 RELATED PARTS TYPICAL APPLICATION PART NUMBER DESCRIPTION COMMENTS LT3922 40V, 2A, 2MHz, Synchronous Boost LED Driver V IN: 2.7V to 40V, VOUT(MAX) = 40V, 5000:1 T rue Color PWM™ Dimming, 5mm × 5mm QFN and TSSOP-28E LT3965 8-Switch Matrix LED Dimmer VIN: 8V to 60V, Digital Programmable 256:1 PWM Dimming, I2C Multidrop Serial Interface TSSOP-28E Package LT3956 80V, 3.3A 1MHz, Step-Up/Down LED Driver V IN: 4.5V to 80V, VOUT(MAX) = 80V, 3000:1 T rue Color PWM Dimming, 5mm × 6mm QFN LT3474 36V, 1A, 2MHz, Step-Down LED Driver VIN: 4V to 36V, VOUT(MAX) = 13.5V, 400:1 T rue Color PWM Dimming, TSSOP-16E LT3475 Dual 36V, 1.5A, 2MHz, Step-Down LED Driver V IN: 4V to 36V, VOUT(MAX) = 13.5V, 3000:1 T rue Color PWM Dimming, TSSOP-20E LT3476 Quad 36V, 1.5A, 2MHz, Step-Up/Down LED Driver V IN: 2.8V to 16V, VOUT(MAX) = 36V, 1000:1 T rue Color PWM Dimming, 5mm × 7mm QFN LT3477 42V, 3A, 3.5MHz, Step-Up/Down LED Driver V IN: 2.5V to 25V, VOUT(MAX) = 40V, 4mm × 4mm QFN and TSSOP-20E LT3478 42V, 4.5A, 2.5MHz, Step-Up/Down LED Driver V IN: 2.5V to 26V, VOUT(MAX) = 42V, 3000:1 T rue Color PWM Dimming, TSSOP-16E LTM8040 36V, 1A, /uni03BCModule, Step-Down LED Driver V IN: 4V to 36V, VOUT(MAX) = 13V, 250:1 T rue Color PWM Dimming, 9mm × 15mm × 4.32mm LGA LTM8042 36V, 1A, /uni03BCModule, Step-Up/Down LED Driver VIN: 3V to 30V, VOUT(MAX) = 36V, 3000:1 T rue Color PWM Dimming, 9mm × 15mm × 2.82mm LGA LT3757 40V, 1MHz, Step-Up Controller VIN: 2.9V to 40V, Positive and Negative Output Voltages, 3mm × 3mm DFN and MSOP-10E 700mA Matrix LED Driver with Individual Dimming for 6 LEDs REN1 10.2k REN2 249k RT 287k 267k RFB2 10k RFB1 RS 100m/uni03A9 LED6 LED2 22nF CBST CREF 2.2µF CVCC 2.2µF CSS 10nF CC 330pF CIN2 2x1µF 33µH LED1 RSS RREF2 110k CIN1 10µF COUT 22nF REN4 249k REN3 10.7k CVDD 2.2µF RSDA 10k RSCL 10k RALERT 10k RDD 100k RREF1 105k RPWM 10k VIN EN/UVLO VREF CTRL PWM SYNC/SPRDINTVCC SS RT RP VC ISP ISN FB VOUT SW BST INTVCC L T3932 VIN 32V VOUT 28V MAX 700mA 350kHz L1: WURTH 74437349330 D1: NEXPERIA BAT46WJ D1-7: NXP PMEG4010CEJ RS: OHMITE LVK12R100DER GND VIN GND EN/UVLO SDA SCL ALERT ADDR1-4 LEDREF PWMCLK VDD L T3965 VDD 3.3V 350kHz
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PWMTG, FAUL T , AND ISMON NOT USED