LT3476 High Current Quad Output LED Driver Fe A Description TM n True Color PWM Dimming Delivers Up to 5000:1 The LT 3476 is a quad output DC/DC converter designed Dimming Ratio (In Boost Configuration) to operate as a constant-current source for driving high n current LEDs. A fixed frequency, current mode architecture LED Current Regulation with High-Side Sense n results in stable operation over a wide range of supply and VADJ Pin Accurately Sets LED Current Sense output voltages. A frequency adjust pin allows the user to Threshold Over Range 10mV to 120mV n program switching frequency between 200kHz and 2MHz Four Independent Driver Channels with 1.5A, 36V to optimize efficiency and external component size. Internal NPN Switches n Frequency Adjust Pin: 200kHz to 2MHz The LT3476 senses output current at the high side of n High Efficiency Conversion = Up to 96% the LED. High side current sensing is the most flexible n Open LED Protection scheme for driving LEDs, allowing buck, boost or buck- n Low Shutdown Current < 10A boost configurations. Each current monitor threshold is n Wide V Range: 2.8V to 16V IN trimmed to within 2.5% at the full scale of 105mV. With n Thermally Enhanced, 38-Lead, 5mm 7mm an external sense resistor, the user programs the output QFN Package current range of each channel. Each of the four regulators is independently operated by that channels PWM signal. This PWM feature allows precise adjustment of the color Applic A mixing or dimming ratio of the LED source. Dimming n RGGB Lighting ratios up to 1000:1 can be achieved. n Automotive and Avionic Lighting L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and True n Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the TFT LCD Backlighting property of their respective owners. n Constant-Current Sources t Al Applic A 100W Quad 1A 8 LED Driver 1000:1 PWM Dimming at 100Hz PV IN 33V CAP1 CAP2 CAP3 CAP4 100m 100m 100m 100m PWM 5V/DIV LED1 LED2 LED3 LED4 2.2F 4 UP TO 1A 1A 1A 1A 8 LEDS I LED 0.22F 0.22F 0.22F 0.22F 500mA/DIV 3476 TA02 5s/DIV 10H 10H 10H 10H 1.05V SW1 SW2 SW3 SW4 4.99k CAP1-4 REF V IN LED1-4 VADJ1-4 2.8V TO 16V LT3476 V IN 100k VC1-4 PWM1-4 PWM1-4 RT SHDN SHDN GND 21k 2.2F 3476 TA01 1nF 3476fb 1 tion ypic tions turesLT3476 Absolute M A Mu M rA p in c F A (Note 1) TOP VIEW V ............................................................................16V IN PWM1-4, SHDN ........................................................16V SW1-4, LED1-4, CAP1-4 ...........................................36V 38 37 36 35 34 33 32 REF, RT, V , VC1-4 ..............................................2V VC1 1 31 NC ADJ1-4 LED1 2 30 NC Operating Junction Temperature Range CAP1 3 29 SW1 (Notes 2 and 3) ...................................... 40C to 125C CAP2 SW1 4 28 Maximum Junction Temperature .......................... 125C LED2 5 27 SW2 Storage Temperature Range .................. 65C to 125C RT 6 26 SW2 39 Lead Temperature (Soldering, 10 sec) ...................300C GND REF 7 25 SW3 LED3 8 24 SW3 CAP3 9 23 SW4 22 CAP4 10 SW4 LED4 11 21 NC VC4 12 20 NC 13 14 15 16 17 18 19 UHF PACKAGE 38-LEAD (5mm 7mm) PLASTIC QFN T = 125C, = 34C/W, = 2C/W JMAX JA JC EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB o r Der i n F MA LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3476EUHF PBF LT3476EUHF TRPBF 3476 38-Lead (5mm 7mm) Plastic QFN 40C to 85C LT3476IUHF PBF LT3476IUHF TRPBF 3476 40C to 125C 38-Lead (5mm 7mm) Plastic QFN LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3476EUHF LT3476EUHF TR 3476 38-Lead (5mm 7mm) Plastic QFN 40C to 85C LT3476IUHF LT3476IUHF TR 3476 38-Lead (5mm 7mm) Plastic QFN 40C to 125C 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: