5 * 4 3 2 1 SEE DEMO MANUAL PVIN E1 PVIN D J1 + C4 56uF,50V 50HVT56M C24 C30 10uF 50V 1210 C2 C1 10uF 50V 1210 SGND + C5 56uF,50V 50HVT56M R1 R33 0 Q1 Q2 BSC035N04LS G 4 0 1 2 3 J2 C25 C31 10uF 50V 1210 SGND E10 5 E11 7 PWM1 E12 8 E13 9 E14 10 SYNC E7 R16 82.5K C18 10nF R20 100K R21 100K R22 100K R23 100K R25 11 14 1 31 29 R36 0 VF NEG PWM1 ISP ISN SYNC PWM_OUT1 FAULT PWM_OUT2 PWM_OUT3 SS RT LED_ISP D4-1 BAT54A 1 + C13 OPT SGND J4 8 7 5 6 4 2 8 7 5 6 4 VC3 LED_ISN Si7234DP 21 R12 0 R13 0 27 PWM1 25 PWM2 23 PWM3 D3-1 BAT54A J5 E5 J3 2 8 7 5 6 4 LED+ LED+ LED+ LED1- LED2- LED3- Q7 Q4 Si7234DP J6 J7 C J8 Si7234DP 4 PWM1 Q8 BSC010N04LS R14 4.02K PWM2 4 Q9 BSC010N04LS 17 PWM3 R27 1k 16 C19 1nF 4 Q10 BSC010N04LS 15 18 VC2 VC1 R29 25.5K B 19 VEE VEE VEE VEE 20 37 35 33 R19 309K 3 22 C17 OPT PWM3 VEE C29 1nF 24 PWM2 26 R18 309K C15 OPT Q6 CTRL3 28 C28 1nF 2 D2 OPT CTRL2 100K R17 309K 4 32 CTRL1 FB 13 + D4-2 BAT54A 3 2 5 6 7 8 4 CTRL2 C10 OPT 1 2 3 2 E6 BAT54A 2 E3 C9 47uF 10V 1206 C16 470uF CTRLT BG 1nF D3-2 C12 470uF 5 6 7 8 6 + 3 C11 470uF 1 2 3 C26 CTRL1 100K OPT LED+ KRL6432 5 6 7 8 C R8 R9 744355182 1 2 3 C14 2.2uF R7 100K 30 Q3 Q5 BSC026N04LS VREF R5 0.003 3 R10 100K L1 0.82uH C8 22uF 6.3V 0805 3 R6 100K 34 EN/UVLO SW 3 C27 1nF INTVCC 3 E4 C6 0.22uF 1 2 1 EN/UVLO PWM3 VIN 0805 E8 PWM2 0 D1 PMEG4002EB BOOST 36 SGND TG E16 12 U1 LT3744EUHE SGND SGND CTRL3 R4 E9 C7 1uF 50V 1 R3 100K 3 R2 OPT E15 1 2 3 SGND 5 6 7 8 VIN E2 1 * 1 3.3V - 36V 5 6 7 8 D R30 R31 25.5K 25.5K C21 C22 C23 10nF 10nF 10nF R32 0.003 KRL6432 B NOTE: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. A A CUSTOMER NOTICE LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. TECHNOLOGY TITLE: SCHEMATIC SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only N/A DATE: IC NO. HIGH CURRENT SYNCHRONOUS STEP-DOWN LED DRIVER LT3744EUHE DEMO CIRCUIT 2339A Wednesday, January 14, 2015 1 SHEET REV. 1 1 OF 1