5 4 3 2 1 E1 INTVCC R8 10k C7 OPT R9 OPT R11 0 R7 0 3 4 6 INTVCC ION 7 DCM CCM 3 2 1 COUT2 100uF + 6.3V 1206 COUT3 330uF 2.5V SANYO 2R5TPE330M9 7343 Q4 OPT + VOUT 1.2V@18A COUT4 330uF 2.5V C SANYO 2R5TPE330M9 7343 J4 GND R10 499k VIN C6 4.7uF 16V 0805 4 E4 VOUT- ONLY APPLY LOAD FROM J3 TO J4 B FSW = 340kHz, TYPICAL R12 10k MODE CUSTOMER NOTICE NOTE: UNLESS OTHERWISE SPECIFIED A 1 2 3 Q3 RJK0330DPB 4 C8 OPT B JP2 1 2 3 BG 12 FCB SGND D1 CMDSH-3 INTVCC INTVCC 11 VRNG COUT1 100uF 6.3V 1206 VOUT+ J3 VOUT 2 PULSE PA0515.471NLT C4 0.1uF 16V VFB PGND INTVCC 8 1 R13 0 VIN- E3 5 BOOST 16 R6 20K 5 5 C5 390pF J2 GND L1 0.47uH SW 14 ITH D SANYO 16SVP180MX E2 16V 5 5 CIN3 180uF 16V 4 1 2 3 R5 13k VIN 10 TG 15 C3 68pF C RUN/SS C1 1uF 1 1 RUN 4 R4 2.2 Q2 OPT CIN4 + 10uF 16V 1210 VIN 4.5V - 14V 13 OFF C2 0.1uF Q1 RJK0305DPB CIN2 1210 OPT 2 1 2 3 ON PGOOD 2 JP1 NC 9 U1 LTC3878EGN E7 RUN/SS CIN1 10uF 16V 1210 R1 100k E6 PGOOD VIN 1 2 3 D VIN+ J1 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. 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: CHECKED: APPROVED: ENGINEER: MIKE S. DESIGNER: TECHNOLOGY KIM T. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: SCHEMATIC A NO RSENSE SIZE A DATE: DWG NO. TM STEP-DOWN DC-DC CONVERTER DC1292A-1 * LTC3878EGN Wednesday, January 07, 2009 2 SHEET 1 REV A-1 1 OF 1