5 4 3 2 1 REVISION HISTORY ECO C6 2.2uF 50V E1 REV DESCRIPTION APPROVED DATE 3 PROTO YAN L. 09/21/12 SVIN SVIN 0805 R2 2 EXTVCC C8 E2 VIN VIN VOUT 4 GND 5 6 EXTVCC ON 2 3 OFF R3 100k 13 JP1 11 INTVCC RUN E9 BOOST 6 PG PGOOD SW C 9 COILCRAFT XAL5030-472MEB FCC JP2 R5 OPT VOUT [2] C9 1uF 0805 R6 4 OPT R7 60.4k 1% VON C 5 RT C3 5.6pF INTVCC R4 3 ITH OPT R9 200k 1% NOTES: UNLESS OTHERWISE SPECIFIED, 1. ALL RESISTOR AND CAPACITOR CASE SIZE ARE 0603. C4 OPT VFB GND R12 619k 1% E3 2 R10 137k 1% R11 84.5k 1% C5 100pF GND 5V 6 4 5 MODE/SYNC COUT2 10uF 16V 1210 INTVCC 3 SYNC COUT1 4.7uF 16V 1210 2 4 E4 VOUT 3.3V 3 7 GND E7 L1 4.7uH SW PGND E10 BURST C1 4.7uF 10 15 SYNC 2 SGND 1 EXTVCC C2 0.1uF MODE / SYNC 1 INTVCC D1 DFLS1200 OPT 1 PGOOD E8 INTVCC 12 1 D E6 EXTVCC RUN VOUT JP5 U1 [3] 14 GND E11 B JP3 [2] VOUT SELECT VIN VOUT 4.5V - 40V 3.3V / 1A 7V - 40V 5V / 1A CUSTOMER NOTICE [3] A 2 3 INTVCC 8 E5 CIN3 10uF 50V 1210 EXTVCC SVIN CIN2 10uF 50V 1210 0805 1uF C7 PVIN + CIN1 OPT B 1 OPT [2] INTVCC D VERSION IC -A LTC3646EDE -B LTC3646EDE-1 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. MI VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. YAN L. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. TITLE: SCHEMATIC SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 TECHNOLOGY 4 3 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 DATE: HIGH EFFICIENCY LOW QUIESCENT CURRENT STEP-DOWN CONVERTER IC NO. REV. LTC3646EDE / LTC3646EDE-1 DEMO CIRCUIT 1731A-A/B 10/04/12 10:19:29 2 SHEET 1 1 3 OF 1 A