LT3746IUHH#TRPBF

LT3746 32-Channel 20mA LED Driver with Buck Controller Features n n n n n n n n Description 6V to 55V Power Input Voltage Range 32 Independent LED Outputs up to 30mA/13V 6-Bit Dot Correction Current Adjustment 12-Bit Grayscale PWM Dimming 0.5µs Minimum LED On Time Adaptive LED Bus Voltage for High Efficiency Cascadable 30MHz Serial Data Interface Full Diagnostic and Protection: Individual Open/Short LED and Overtemperature Fault Applications Large Screen Display LED Backlighting Mono-, Multi-, Full-Color LED Displays n LED Billboards and Signboards n n 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. The LT®3746 integrates a 32-channel LED driver with a 55V buck controller. The LED driver lights up to 30mA/13V of LEDs in series per channel, and the buck controller generates an adaptive bus voltage supplying the parallel LED strings. Each channel has individual 6-bit dot correction current adjustment and 12-bit grayscale PWM dimming. Both dot correction and grayscale are accessible via a serial data interface in TTL/CMOS logic. The LT3746 performs full diagnostic and protection against open/short LED and overtemperature fault. The fault status is sent back through the serial data interface. The 30MHz fully-buffered, skew-balanced, cascadable serial data interface makes the chip extremely suitable for large screen LCD dynamic backlighting and mono-, multi-, full-color LED displays. Typical Application 32-Channel LED Driver, 1MHz Buck, 3 LEDs 10mA to 30mA per Channel, 500Hz 12-Bit Dimming VIN 13V TO 42V 0.47µF VIN EN VCC 3V TO 5.5V EN/UVLO 22µH 100k VCC 10µF SS GND LT3746 10nF 2.048MHz CLOCK 10k ISN FB ISET 60.4k ISP C1 2 × 47µF . .. RT 33mΩ 80.6k SYNC 46.4k 4.7µF CAP GATE TSET 32.4k LED00 LED01 LED02 PWMCK .. . LED29 LED30 LED31 TTL/CMOS SCKI SCKO SDI SDO LDI LDO TTL/CMOS 3746 TA01 3746fa For more information www.linear.com/3746 1 LT3746 Absolute Maximum Ratings Pin Configuration (Note 1) RT SS FB ISN ISP CAP GATE VIN TSET TOP VIEW ISET VIN ........................................................................... 57V CAP.......................................................... VIN – 8V to VIN GATE...............................................................CAP to VIN LED00 to LED31, ISP, ISN.......................................... 13V ISP..................................................ISN – 1V to ISN + 1V FB, RT, TSET, ISET........................................................ 2V VCC................................................................–0.3V to 6V SCKI, SCKO, SDI, SDO, LDI, LDO, PWMCK, SYNC, SS, EN/UVLO.............................................. –0.3V to VCC Operating Junction Temperature Range (Notes 2, 3).............................................–40°C to 125°C Storage Temperature Range...................–65°C to 125°C 56 55 54 53 52 51 50 49 48 47 EN/UVLO 1 46 SYNC LED15 2 45 LED16 LED14 3 44 LED17 LED13 4 43 LED18 LED12 5 42 LED19 LED11 6 41 LED20 LED10 7 40 LED21 LED09 8 39 LED22 LED08 9 38 LED23 57 GND 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 SCKO GND SDO LDO PWMCK VCC LDI SDI GND SCKI 19 20 21 22 23 24 25 26 27 28 UHH PACKAGE 56-LEAD (5mm × 9mm) PLASTIC QFN TJMAX = 125°C, θJA = 32°C/W, θJC = 2.0°C/W EXPOSED PAD (PIN 57) IS GND, MUST BE SOLDERED TO PCB order information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3746EUHH#PBF LT3746EUHH#TRPBF 3746 56-Lead (5mm × 9mm) Plastic QFN –40°C to 125°C LT3746IUHH#PBF LT3746IUHH#TRPBF 3746 56-Lead (5mm × 9mm) Plastic QFN –40°C to 125°C 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: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 2 3746fa For more information www.linear.com/3746 LT3746 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 24V, VCC = 3.3V, VEN/UVLO = 1.5V, VFB = 1.5V, VISP = VISN = 0V, RT = 105k, RISET = 60.4k, CCAP = 0.47µF to VIN, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Supply VIN VIN Operating Voltage IVIN VIN Supply Current VCC VCC Operating Voltage IVCC VCC Supply Current (Note 4) l 6 VEN/UVLO = 0V No Switching 55 0.2 0.4 l 3 VEN/UVLO = 0V LED Channel Off, 30MHz Data Off LED Channel On, 30MHz Data Off LED Channel On, 30MHz Data On 2 0.55 V µA mA 5.5 V 0.1 3.3 10 19 1 4.0 µA mA mA mA Undervoltage Lockout (UVLO) IEN/UVLO VCC UVLO Threshold VCC Rising VCC Falling 2.82 2.61 2.89 2.68 2.96 2.75 V V EN/UVLO Shutdown Threshold UVLO Threshold IVCC