. LT3745 16-Channel 50mA LED Driver with Buck Controller Fea T Descrip T n 6V to 55V Power Input Voltage Range The LT 3745 integrates a 16-channel LED driver with a 55V n 16 Independent LED Outputs Up to 75mA/36V buck controller. The LED driver lights up to 75mA/36V of n 3% LED Current Matching at 50mA (Typ 1%) LEDs in series per channel, and the buck controller gener- n 6-Bit Dot Correction Current Adjustment ates an adaptive bus voltage supplying the parallel LED n 12-Bit Grayscale PWM Dimming strings. Each channel has individual 6-bit dot correction n 0.5s Minimum LED On-Time current adjustment and 12-bit grayscale PWM dimming. n Adaptive LED Bus Voltage for High Efficiency Both dot correction and grayscale are accessible via a n Cascadable 30MHz Serial Data Interface serial data interface in TTL/CMOS logic. A 3% LED cur- n Full Diagnostic and Protection: Individual Open/Short rent matching and a 0.5s minimum LED on-time can be LED and Overtemperature Fault achieved at 50mA per channel. n 40-Lead 6mm 6mm QFN Package The LT3745 performs full diagnostic and protection against open/short LED and overtemperature fault. The a T fault status is sent back through the serial data interface. n Large Screen Display LED Backlighting The 30MHz fully-buffered, skew-balanced, cascadable n Mono-, Multi-, Full-Color LED Displays serial data interface makes the chip extremely suitable n LED Billboards and Signboards for large screen LCD dynamic backlighting and mono-, L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and multi-, full-color LED displays. True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical a T 16-Channel LED Driver, 1MHz Buck, 10 LEDs, 25mA to 75mA per Channel, 500Hz 12-Bit Dimming V IN 42V TO 55V 0.47F 4.7F V CAP IN EN EN/UVLO GATE 47H 25m 100k V CC 3V TO 5.5V V CC 267k 10F SYNC GND C1 2 47F RT ISP LT3745 10k SS ISN 46.4k 10nF FB I SET LED00 T SET 60.4k LED01 32.4k LED02 . 2.048MHz CLOCK PWMCK LED13 LED14 LED15 SCKI SCKO TTL/CMOS SDI SDO TTL/CMOS LDI LDO 3745 TA01 3745f 1 ion pplica ions pplica ion uresLT3745 a Te Maxi Mu M r a T p c F T (Note 1) V .......................................................................... 57V TOP VIEW IN CAP ......................................................... V 8V to V IN IN GATE ..............................................................CAP to V IN 40 39 38 37 36 35 34 33 32 31 LED00 to LED15, ISP, ISN .........................................40V EN/UVLO 1 30 SYNC ISP .................................................ISN 1V to ISN + 1V LED07 2 29 LED08 FB, RT, T , I ....................................................... 2V SET SET LED06 3 28 LED09 V ...............................................................0.3V to 6V CC LED05 4 27 LED10 SCKI, SCKO, SDI, SDO, LDI, LDO, PWMCK, SYNC, LED04 41 5 26 LED11 GND SS, EN/UVLO ............................................. 0.3V to V LED03 6 25 LED12 CC LED02 7 24 LED13 Operating Junction Temperature Range LED01 8 23 LED14 (Notes 2, 3) LED00 9 22 LED15 LT3745E ............................................40C to 125C GND 10 21 GND LT3745I .............................................40C to 125C 11 12 13 14 15 16 17 18 19 20 Storage Temperature Range ..................65C to 125C UJ PACKAGE 40-LEAD (6mm 6mm) PLASTIC QFN T = 125C, = 34C/W, = 2.5C/W JMAX JA JC EXPOSED PAD (PIN 41) IS GND, MUST BE SOLDERED TO PCB o r D i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3745EUJ PBF LT3745EUJ TRPBF 3745 40-Lead (6mm 6mm) Plastic QFN 40C to 125C LT3745IUJ PBF LT3745IUJ TRPBF 3745 40-Lead (6mm 6mm) 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. Consult LTC Marketing for information on nonstandard lead based finish parts. For more information on lead free part marking, go to: