5 4 3 2 1 MAIN CIRCUIT C7 4.7UF 6.3V VCC VBST1 21 5 ILSET TG1 TG1 20 TG1 6 CCM SW1 SW1 19 SW1 9 NC ISVOUT 10 13 SW2 VBST2 11 D2 CMDSH-3-LTC TG2 TG2 L1 2.2UH PHILIPS TDK RLF7030T-2R2M5R4 7 8 C11 0.1UF VOUT E7 VOUT 3.3V@3A C14 47UF 6.3V 1210 C16 150UF 6.3V 6032 D4 PMEG1030EH C15 0.1UF E8 GND SW2 BG2 BG2 5 SW2 B Q2B FDS6894A 4 3 B D3 PMEG2020EJ Q2A FDS6894A 2 C9 0.22UF 10V 25 TG2 12 Q1B FDS6894A 4 VDRV 16 15 BG2 14 ISSW2 C BG1 BG1 BG1 17 2 R10 10K GND Q1A FDS6894A 2 ISSW1 18 8 MODE E6 1 7 RT C13 220UF 16V SANYO 16CV220KX C10 0.1UF 1 MODE MODE C8 0.22UF 10V OPT 2 R8 49.9K R9 10K E3 R7 42.2K C12 22UF 16V 1210 E5 VIN 2.7V-10V 1 R6 127K CCM C ISVIN 22 GND E2 2 VC 4 VSENSE C5 OPT CCM R4 31.6K DO1813P-332HCB 6 C4 470PF VCC 23 D1 CMDSH-3-LTC 2 1 5 R5 215K 3 FB VIN L2 3.3UH 3 R2 10K VIN 24 8 C2 220PF C3 10PF 1 RUN/SS 2 C1 2200PF R1 215K CUTTABLE TRACE C6 0.1UF U1 LTC3785EUF 1 R3 127K D 0603 R12 OPT 7 E1 1 VCC 6 D NOTES: UNLESS OTHERWISE SPECIFIED A 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE 0402. 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 CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. CONTRACT NO. APPROVALS DRAWN: TITLE: SCHEMATIC CHECKED: APPROVED: ENGINEER: DAVID B. DESIGNER: 4 3 10W BUCK-BOOST SYNCHRONOUS CONVERTER SIZE A THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 TECHNOLOGY KIM T. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: 2 DWG NO. DC957A-1 * LTC3785EUF Monday, September 17, 2007 SHEET 1 REV A-1 1 OF 1 A