LT3932/LT3932-1 36V, 2A Synchronous Step-Down LED Driver FEATURES DESCRIPTION n 1.5% LED Current Regulation The LT 3932 , featuring the Silent Switcher architecture n 1.2% Output Voltage Regulation to minimize EMI/EMC emissions, utilizes fixed-frequency, n 5000:1/10000+:1 PWM Dimming at 100Hz peak current control and provides PWM dimming for a (LT3932/LT3932-1) string of LEDs. The LED current is programmed by an n 128:1 Internal PWM Dimming analog voltage or the duty cycle of pulses at the CTRL pin. n Spread-Spectrum Frequency Modulation An output voltage limit can be set with a resistor divider n Silent Switcher Architecture for Low EMI to the FB pin. n 3.6V to 36V Input Voltage Range The switching frequency is programmable from 200kHz to n 0V to 36V LED String Voltage 2MHz by an external resistor at the RT pin or by an exter- n 200kHz to 2MHz with SYNC Function nal clock at the SYNC/SPRD pin. With the optional spread n 99.9% Maximum Duty Cycle spectrum frequency modulation enabled, the frequency n 20:1 Analog or Duty Cycle LED Current Control varies from 100% to 125% to reduce EMI. The LT3932 n Open/Short LED Protection and Fault Indication also includes a driver for an external, high side PMOS for n Accurate LED Current Sense with Monitor Output PWM dimming and an internal PWM signal generator for n Programmable UVLO analog control of PWM dimming when an external signal is n Thermally Enhanced 28-Pin (4mm 5mm) QFN not available. The LT3932-1 permits higher dimming ratios. n AEC-Q100 Qualified for Automotive Applications Additional features include an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault report- APPLICATIONS ing for open-circuit and short-circuit load conditions, and n Automotive Lighting thermal shutdown. n Industrial and General Purpose Lighting 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. n Machine Vision Systems TYPICAL APPLICATION 2A LED Driver with Internal PWM Dimming INTV CC Internal PWM Dimming V IN V BST IN 20V 8.2H 22nF 274k SW EN/UVLO 10F 2x1F V OUT SW 30.1k 20V/DIV 110k C OUT LT3932 FB 100F PWMTG 10k 2A MAX V REF 10V/DIV GND IL 100k CTRL 1A/DIV 2.2F 100k PWM ISP ILED 50m 1A/DIV 3932 TA01b INTV ISN CC 2s/DIV 100k PWM = 1.078V PWMTG 2.2F (8% PWM DUTY RATIO) FAULT FAULT ISMON ISMON SYNC/SPRD SS RT RP V C 9V 45.3k 28.7k 162k 2MHz 7.8kHz 10nF 100nF 3932 TA01a Rev C 1 Document Feedback For more information www.analog.comLT3932/LT3932-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UVLO ............................................................40V IN ISP, ISN, and V ....................................................40V OUT ISP ISN ...............................................................0.3V 28 27 26 25 24 23 CTRL and FB ............................................................3.3V V 1 22 GND REF PWM, SYNC/SPRD, and FAULT ...................................6V SS 2 21 V IN SS and V ................................................................3.3V C V 3 20 V C IN SW, BST, INTV , V , ISMON, PWMTG, RT, FB 4 19 SW CC REF 29 GND ISP 5 18 SW and RP ............................................................... (Note 2) ISN 6 17 V IN Operating Junction Temperature Range (Notes 3, 4) ISMON 7 16 V IN LT3932E/LT3932I .............................. 40C to 125C FAULT 8 15 GND LT3932H ............................................ 40C to 150C 9 10 11 12 13 14 Storage Temperature Range .................. 65C to 150C UFD PACKAGE 28-LEAD (4mm 5mm) PLASTIC QFN = 25C/W (MEASURED ON DC2286A) JA EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3932EUFD PBF LT3932EUFD TRPBF 3932 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3932IUFD PBF LT3932IUFD TRPBF 3932 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3932HUFD PBF LT3932HUFD TRPBF 3932 28-Lead (4mm 5mm) Plastic QFN 40C to 150C LT3932EUFD-1 PBF LT3932EUFD-1 TRPBF 39321 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3932IUFD-1 PBF LT3932IUFD-1 TRPBF 39321 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3932HUFD-1 PBF LT3932HUFD-1 TRPBF 39321 28-Lead (4mm 5mm) Plastic QFN 40C to 150C AUTOMOTIVE PRODUCTS** LT3932EUFD WPBF LT3932EUFD WTRPBF 3932 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3932IUFD WPBF LT3932IUFD WTRPBF 3932 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3932HUFD WPBF LT3932HUFD WTRPBF 3932 28-Lead (4mm 5mm) Plastic QFN 40C to 150C Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. **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 thesemodels. Rev C 2 For more information www.analog.com RP CTRL RT EN/UVLO SYNC/SPRD V IN PWM INTV CC PWMTG BST V GND OUT