. LT3746 32-Channel 20mA LED Driver with Buck Controller Fea T Descrip T n 6V to 55V Power Input Voltage Range The LT 3746 integrates a 32-channel LED driver with a 55V n 32 Independent LED Outputs up to 30mA/13V buck controller. The LED driver lights up to 30mA/13V of n 6-Bit Dot Correction Current Adjustment LEDs in series per channel, and the buck controller gener- n 12-Bit Grayscale PWM Dimming ates an adaptive bus voltage supplying the parallel LED n 0.5s Minimum LED On Time strings. Each channel has individual 6-bit dot correction n Adaptive LED Bus Voltage for High Efficiency current adjustment and 12-bit grayscale PWM dimming. n Cascadable 30MHz Serial Data Interface Both dot correction and grayscale are accessible via a n Full Diagnostic and Protection: Individual Open/Short serial data interface in TTL/CMOS logic. LED and Overtemperature Fault The LT3746 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. The 30MHz fully-buffered, skew-balanced, cascadable n Large Screen Display LED Backlighting serial data interface makes the chip extremely suitable n Mono-, Multi-, Full-Color LED Displays for large screen LCD dynamic backlighting and mono-, n LED Billboards and Signboards multi-, full-color LED displays. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical a T 32-Channel LED Driver, 1MHz Buck, 3 LEDs 10mA to 30mA per Channel, 500Hz 12-Bit Dimming V IN 13V TO 42V 0.47F 4.7F V CAP IN EN EN/UVLO GATE 22H 33m 100k V CC 3V TO 5.5V V CC 80.6k 10F SYNC C1 GND 2 47F RT ISP LT3746 10k SS ISN 46.4k 10nF FB I SET LED00 T SET 60.4k LED01 32.4k LED02 . 2.048MHz CLOCK PWMCK LED29 LED30 LED31 SCKI SCKO TTL/CMOS SDI SDO TTL/CMOS LDI LDO 3746 TA01 3746fa 1 For more information www.linear.com/3746 ion pplica ions pplica ion uresLT3746 a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW V .......................................................................... 57V IN CAP ......................................................... V 8V to V IN IN GATE ..............................................................CAP to V IN 56 55 54 53 52 51 50 49 48 47 LED00 to LED31, ISP, ISN .........................................13V EN/UVLO 1 46 SYNC ISP .................................................ISN 1V to ISN + 1V LED15 2 45 LED16 LED14 LED17 FB, RT, T , I ....................................................... 2V 3 44 SET SET LED13 4 43 LED18 V ...............................................................0.3V to 6V CC LED12 5 42 LED19 SCKI, SCKO, SDI, SDO, LDI, LDO, PWMCK, SYNC, LED11 LED20 6 41 SS, EN/UVLO ............................................. 0.3V to V CC LED10 7 40 LED21 Operating Junction Temperature Range LED09 8 39 LED22 (Notes 2, 3) ............................................40C to 125C LED08 9 38 LED23 57 GND Storage Temperature Range ..................65C to 125C LED07 10 37 LED24 LED06 11 36 LED25 LED05 12 35 LED26 LED04 13 34 LED27 LED03 14 33 LED28 LED02 15 32 LED29 LED01 16 31 LED30 LED00 17 30 LED31 GND 18 29 GND 19 20 21 22 23 24 25 26 27 28 UHH PACKAGE 56-LEAD (5mm 9mm) PLASTIC QFN T = 125C, = 32C/W, = 2.0C/W JMAX JA JC EXPOSED PAD (PIN 57) IS GND, MUST BE SOLDERED TO PCB Der in F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3746EUHH PBF LT3746EUHH TRPBF 3746 56-Lead (5mm 9mm) Plastic QFN 40C to 125C LT3746IUHH PBF LT3746IUHH TRPBF 3746 56-Lead (5mm 9mm) 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 non-standard lead based finish parts. For more information on lead free part marking, go to: