5 4 3 2 1 REVISION HISTORY ECO - D VIN 2.7V TO 5.5V GND VINE1 APPROVED DESCRIPTION PRODUCTION 3 DATE CHARLIE Z. 08/23/10 VIN+ E2 J2 J1 REV D CIN1 + 220uF 6.3V + CIN2 MODE 1 2 BURST 3 PS 220uF 6.3V CIN3 R1 INTVCC 100K + CCM (OPT) CIN4 4 VIN + JP2 E3 PLLIN (OPT) R3 0 Ohm R2 10 C1 C2 2.2uF 10V 7 0603 4.7uF 10V C5 C3 100pF 0.1uF R5 C FREQ/PLLFLTR 1 400K 19 82.5K 1% MODE/PLLIN C+ 2 20 C16 3 EXTCLK JP3 R7 C4 TG SW BOOST VPUMP VIN2 R9 23 5.90K C8 2200pF ITH C9 150pF INTVCC 21 RUN BG 3 OFF Q1 SiR438DP NOTE: 1. WHEN RESISTOR SENSING IS IMPLEMENTED DO NOT POPULATE R8 AND R15. 2. WHEN DCR SENSING IS IMPLEMENTED, SHORT RS1 AND DO NOT POPULATE R11 AND R12. Q2 (OPT) R13 22 C11 0.1uF 0 Ohm 18 R6 16 0 Ohm R22 13 C7 4.7uF 10V 15 VIN2 C14 4.7uF 10V 14 INTVCC 0 Ohm C6 0.1uF R8 (OPT) RS1 59PR9875N Vitec 0.002 1% J3 VOUT 1.5V / 15A COUT1 100uF 6.3V R15 (OPT) COUT2 (OPT) + COUT3 COUT4 COUT5 COUT6 330uF + 330uF + (OPT) + (OPT) 4V 4V J4 GND D1 CMDSH-3 R23 R11 100 0 Ohm R12 100 E7 VOUT- R24 C15 4.7uF 10V Q3 SiR438DP 0 Ohm 5 VIN Q4 (OPT) R10 R26 R16 R17 100K 100K R25 0 Ohm 2 PGOOD SENSE- 10 VIN2 (Opt) B VIN E9 E10 VIN2 TRACK/SS SENSE+ 3 PGOOD C E4 VOUT+ L1 0.4uH 0 Ohm TRACK E8 CIN6 10uF 16V 1206 17 1 2 B VIN1 0.01uF E6 ON C- U1 LTC3852EUDD RUN JP1 RUN 12 FREQ/PLLFLTR 1000pF 1K 8 CIN5 10uF 16V 1206 SHDN FB GND1 GND GND2 NC NC 11 25 4 6 9 C12 1000pF R14 (OPT) R19 20K 1% R20 17.4K 1% 1 24 C13 (OPT) R21 0 Ohm 0805 CUSTOMER NOTICE A APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. TECHNOLOGY RB 5 4 3 LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY N/A SCALE = NONE 2 A CHARLIE Z. TITLE: SCHEMATIC SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 1630 McCarthy Blvd. Milpitas, CA 95035 www.linear.com Phone: (408)432-1900 Fax: (408)434-0507 DATE: LOW VIN, HIGH EFFICIENCY STEP-DOWN DC/DC CONVERTER IC NO. REV. LTC3852EUDD 4 DEMO CIRCUIT 1270A Thursday, October 21, 2010 SHEET 1 1 OF 1