5 4 3 2 1 D2 PDZ10B 2 1 R6 10k 1 Q2 FZTA42 R1 274K 1% 1 2 3 U1 LTC1871EMS-1 2 ITH VIN 9 FB INTVCC 8 3 RC1 12.4K 1% 4 RT 80.6K 1% 3 B 2 1 5 C5 0.1uF R10 33.2K 50V 1% C6 0.1uF R11 18K BURST SENSE 10 C3 0.1uF 50V C4 OPT GATE 7 FREQ MODE/SYNC JP2 MODE 2 Q1 HAT2169H GND 6 1 GND E3 VOUT 12V@3A VOUT COUT1 33uF COUT2 16V COUT3 1812 COUT4 L1B 4.7uH DRQ127-4R7 4 E2 D1 PDS1040 3 1812 R7 47 CVCC 4.7uF 10V 3 2 1 R9 10K Q3 BC847BF RUN 680uF 35V SANYO 35CE680AX C + CSYS 150uF 16V E4 2 OPT 1 1812 CDC1 10uF,25V VIN 5V-20V + CIN4 CDC2 10uF,25V R2 OPT 5 CC2 CC1 R3 R4 6800pF 12.4K 110K 1% 1% CIN1 22uF CIN2 25V CIN3 1812 L1A 4.7uH DRQ127-4R7 R5 133K 1% C E1 VIN 3 OFF D GND 1 2 3 ON 2 4 4 JP1 RUN 3 1 JP3 U1 BIAS 3 9V 2 1 VIN D R8 0.005 2010 1206 B CONT. 50V CUSTOMER NOTICE NOTE: UNLESS OTHERWISE SPECIFIED A 1. ALL RESISTORS ARE IN OHMS, 0805. ALL CAPACITORS ARE IN MICROFARADS, 0805. CONTRACT NO. 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 4 3 APPROVALS DRAWN: TECHNOLOGY KIM T. CHECKED: TITLE: SCHEMATIC APPROVED: ENGINEER: GORAN P. DESIGNER: 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only SIZE A DATE: A HIGH EFFICIENCY SEPIC DWG NO. DC1225A-1 * LTC1871EMS-1 Thursday, October 18, 2007 2 SHEET 1 REV A-1 1 OF 1