5 4 3 2 1 REVISION HISTORY ECO REV __ R1 0 VIN C1 2.2uF 100V 1812 C3 47uF/63V + C4 0.1uF 100V INTVCC GND C5 OPT R4 100k E2 U1 PGOOD R9 OPT VIN FREQ PGOOD EXTVCC VFB INTVCC INTVCC 16 C6 2.2uF 0805 C7 1uF R11 OPT TRACK 1 E5 10 R14 OPT 0805 RUN 1 6 R12 OPT VIN C9 0.01uF 5 2 4 3 OFF C11 OPT R16 OPT JP1 R17 15K C12 2.2nF 18 3 TRACK/SS RUN SENSE- SENSE+ SGND INTVCC BOOST R15 2 TG PLLIN/MODE B INTVCC INTVCC R19 OPT 4 BG Q1 Si7850DP RS1 0.008 1210 VOUT VOUT 13 15 4 L1 4.7uH E6 C15 10uF 1206 D2 OPT 4 1 2 3 C18 OPT ILIM D1 DFLS1100 12 C13 0.1uF SGND E8 14 SGND PGND C10 2.2uF 100V VIN 21 20 C R13 100 8 ITH SW R18 1K R10 0 7 C8 2.2pF C14 180pF SYNC R7 115K 2 9 5 17 EXTVCC ON R5 357K 0805 R6 41.2K C16 330uF 4.0V 4TPE330MIC2 + C17 1uF B MODE R20 100K 3.3V @ 5A 1 2 3 11 R8 OPT C D 5 19 E4 DATE 06-05-12 LTC3891EFE VOUT E3 VICTOR K. R2 0 R3 OPT 1 2 3 C2 OPT APPROVED INTVCC 5 E1 4.5V UP TO 60V DESCRIPTION PRODUCTION VOUT VIN D 1 GND 2 1 4 3 PULSE SKIP 6 5 BURST MODE Q2 Si7850DP R21 OPT CCM Q3 OPT E7 JP2 NOTES: GND E9 GND E10 A 1. FOR SYNCHRONIZATION REMOVE JUMPER JP2 'MODE' AND CONNECT SOURCE OF THE SYNC SIGNAL TO TERMINALS E8 'SYNC' AND E9 'GND' 2. FOR Q1 AND Q2 FOLLOWING MOSFETs CAN BE USED RJK0651DPB, RENESAS HAT2266H, RENESAS BSC100N06LS3G, INFINEON 2. FOR C16 FOLLOWING CAPACITORS CAN BE USED 4TPE330MIC2, SANYO 6TPE330MIC2, SANYO 5 4 CUSTOMER NOTICE 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 3 TECHNOLOGY AK VICTOR K 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: SCHEMATIC LOW QUIESCENT CURRENT HIGH VOLTAGE STEP-DOWN CONVERTER SIZE N/A SCALE = NONE 2 DATE: IC NO. LTC3891EFE REV. 1 DEMO CIRCUIT 1695B Friday, July 06, 2012 SHEET 1 1 OF 1 A