1 2 3 4 5 6 7 8 REVISION HISTORY ECO REV __ R10 0 TRK/SS1 DESCRIPTION 1 PRODUCTION APPROVED YI S. DATE 1-17-11 TRK/SS1 E1 R12 (OPT) A C6 10nF VIN A VIN * R13 C7 C8 220pF R25 8.2K R32 (OPT) 6 4 R20 20.0k 1 2 3 E10 R34 (OPT) C20 (OPT) 10 8 * R26* L2- C18 22pF 11 * * R27 R29 1 2 3 4 BG2 VOUT1 E5 3 8 7 R16 0 * J1 COUT2 22uF 6.3V 1206 COUT1 220uF 4V POSCAP C5 1uF 6.3V VOUT1 3.3V / 5A COUT5 (OPT) POSCAP E6 GND 24 23 VINF R21 10 CIN2 4.7uF 50V 1206 VIN 22 C14 0.1uF 21 TG2 7 18 RUN2 RUN2 * * VOUT2 E8 * L2 2.4uH CDEP85-2R4MC-50 2 17 RSNS2 COUT4 22uF 6.3V 1206 COUT3 220uF 4V POSCAP C17 1uF 6.3V VOUT2 2.5V / 5A COUT6 (OPT) POSCAP E9 GND C19 0.1uF VSW2 SW2 J2 Q2B FDS6982AS SENSE2+ SGND L2- VSW2 0805 R36 0 TG2 12 INTVCC D3 BOOST2 B Q2A FDS6982AS R23 19 TK/SS2 SENSE2- S2+ BG2 20 C13 4.7uF ITH2 * JP3 MODE C10 (OPT) INTVCC VFB2 VOUT2 E11 VIN VFB1 INTVCC SYNC 1 ITH1 C15 S2+ SYNC BG1 PGND 9 R40 0 R18 0 27 TK/SS1 TRK/SS2 R22 R30 63.4K * RSNS1 Q1B FDS6982AS 25 4 ON OFF BOOST1 L1- L1 2.4uH CDEP85-2R4MC-50 2 INTVCC JP2 RUN2 RUN2 5 R19 20.0k C12 330pF RUN2 26 * TRK/SS1 R17 C11 2.2nF VIN SENSE1- R6 3 OFF C16 (OPT) MODE TG1 C9 2.2nF B SW1 BG1 8 7 ON * L1- VSW1 GND 1 R15 10K C4 0.1uF 2 1 2 3 D1 1 JP1 RUN1 RUN1 28 * 3 E3 1 * Q1A FDS6982AS 5 6 R9 90.9K R14 R39 (OPT) 4 VIN 4.5V - 26V CIN4 22uF 35V S1+ SENSE1+ PGOOD C3 22pF VIN 2 FREQ S1+ * E7 TG1 VSW1 RUN1 R35 0 R11 R24 (OPT) SYNC 1 U1 LTC3869IGN-2 RUN1 RUN1 INTVCC 2 VOUT1 EXTVCC R4 (OPT) E4 16 INTVCC R33 100K 15 C1 10nF TRK/SS2 14 R1 (OPT) FSW = 400KHz, TYPICAL 13 TRK/SS2 R7 100K E2 5 6 VOUT1 CIN1 4.7uF 50V 1206 PGOOD PULSE SKIP E12 C21 0.1uF BURST FCC E13 EXTVCC C C CIN5 (OPT) VINF VIN TG1 CIN6 (OPT) TG2 8 R41 (OPT) 8 INTVCC VSW1 1 VSW2 1 7 6 5 7 6 5 BG2 (OPT) 3 2 PHASE1 PHASE2 Q4 Si4816BDY 4 2 Q3 Si4816BDY (OPT) 4 3 BG1 OPTIONAL MOSFETS & CIN * ASST DESC RSNS1 R11 R14 -A RSENSE 0.006 Ohm 10 Ohm 10 Ohm 1nF (OPT) (OPT) (OPT) -B DCR SENSE (OPT) (OPT) 0.1uF SHORT 3.92K 4.99k D (OPT) C7 J1 R6 R13 R17 C15 J2 R23 RSNS2 R29 R26 (OPT) 0.006 Ohm 10 Ohm 10 Ohm 1nF R22 (OPT) (OPT) (OPT) 0 Ohm (OPT) (OPT) (OPT) 0.1uF SHORT 3.92K 0 Ohm R27 (OPT) 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. 4.99k NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS AND CAPACITORS ARE 0603 APPROVALS PCB DES. HZ APP ENG. YI S. TECHNOLOGY TITLE: SCHEMATIC SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 1 2 3 4 5 6 N/A SCALE = NONE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DUAL OUTPUT, DUAL PHASE 5A SYNCHRONOUS BUCK CONVERTER IC NO. LTC3869IGN-2 DEMO CIRCUIT 1798A-A/B REV. 1 DATE: Wednesday, June 29, 2011 7 SHEET 1 8 OF 1 D