5 4 3 2 PVIN 33V max VIN 2.8V- 16V R3 33.2K R2 66.5K R24 33.2K R25 66.5K R26 33.2K R27 66.5K R28 33.2K R29 66.5K C4 C1 4.7uF 50V (OPT) 1uF 7 REF 37 VADJ1 GND PVIN C3 2.2uF 35V C2 2.2uF 35V E15 D GND E16 Vin 33 D E2 E1 22nF SHDN 18 C6 1 U1 LT3476EUHF CAP1 3 LED1 2 PVIN R1 0.1 LED1+ LED1- E3 S1 E4 SW1 SW1 SW2 SW3 SW4 35 PWM1 34 PWM2 C14 (OPT) R6 C15 (OPT) R7 0 C16 (OPT) R9 0 C17 (OPT) R10 C10 1nF C11 1nF C12 1nF 0 0 C13 1nF CAP3 9 LED3 8 LED2+ LED2- E5 38 VC2 PVIN R5 0.1 LED3- LED3+ E7 C7 0.33uF S4 DFLS140 0 D3 C8 0.33uF S6 2 DFLS140 0 10uH L3 D4 R8 0.1 LED4+ LED4- E9 R23 ** S7 E10 C9 0.33uF S8 L4 0 2 DFLS140 SW4 23 SW4 22 6 RT C SW3 PVIN CAP4 10 LED4 11 12 VC4 10uH L2 R22 ** S5 E8 10uH B SW4 CUSTOMER NOTICE 4 ** SW2 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 R21 1 13 VC3 ** Remove for faster LED turn-off. A S3 E6 SW3 25 SW3 24 1 VC1 R11 21K 0.1 1 17 PWM3 16 PWM4 PWM4 R4 N/C N/C N/C N/C N/C N/C PWM3 PVIN 2 19 20 21 30 31 32 PWM2 E13 PWM3 D2 SW2 27 SW2 26 39 GND E12 PWM2 E14 PWM4 B CAP2 4 LED2 5 PWM1 PWM2 PWM3 PWM4 PWM1 10uH 1 14 VADJ4 2 DFLS140 L1 0 15 VADJ3 E11 PWM1 C5 0.33uF S2 R20 ** SW1 29 SW1 28 36 VADJ2 C D1 1 3 CONTRACT NO. APPROVALS DRAWN DATE HELEN 6/22/06 Walker Bai 6/22/06 CHECKED APPROVED ENGINEER DESIGNER Monday, August 28, 2006 2 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 A TITLE LT3476EUHF Quadruple High Power LED Driver in Buck Mode SIZE CAGE CODE SCALE: FILENAME: DWG NO REV A DC976A SHEET 1 1 OF 1 5 4 3 D 2 S1 Si2303BDS 3 D S2 Q2 1 3 R13 2N7002 2 4.99K PWM1 1 4.99K 2 S3 Si2303BDS 3 S4 Q3 Q4 1 R14 4.99K 3 R15 2N7002 2 4.99K C PWM2 1 C 2 Si2303BDS 3 Q5 S6 Q6 1 S5 4.99K 3 R17 2N7002 2 4.99K PWM3 1 R16 2 S7 Si2303BDS 3 Q7 S8 Q8 1 4.99K 3 R19 4.99K PWM4 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. A 4 B 2N7002 2 1 R18 5 1 Q1 R12 B 2 3 CONTRACT NO. APPROVALS DRAWN DATE HELEN 6/22/06 Walker Bai 6/22/06 CHECKED APPROVED ENGINEER DESIGNER Tuesday, July 25, 2006 2 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 A TITLE LT3476EUHF Quadruple High Power LED Driver in Buck Mode SIZE CAGE CODE SCALE: FILENAME: DWG NO REV A DC976A SHEET 1 2 OF 2