5 4 3 2 1 REVISION HISTORY ECO C6 2.2uF 50V E1 REV DESCRIPTION 4 PROD APPROVED DATE YAN L. 09/21/12 SVIN SVIN 0805 R2 2 EXTVCC C8 E2 2 3 OFF R3 100k 15 JP1 6 PG SW COILCRAFT XAL5030-472 8 COUT1 4.7uF 16V 1210 MODE/SYNC VON COUT2 10uF 16V 1210 VOUT [2] C9 1uF 0805 C 5 RT C3 5.6pF INTVCC R4 3 ITH OPT NOTES: UNLESS OTHERWISE SPECIFIED, 1. ALL RESISTOR AND CAPACITOR CASE SIZE ARE 0603. C4 OPT VFB E3 2 R10 137k 1% R11 84.5k 1% C5 100pF GND 5V R7 60.4k 1% GND R12 619k 1% 4 4 R9 200k 1% B VOUT 2 R5 OPT E4 L1 4.7uH 11 SW 3 R6 OPT JP2 12 1 FCC GND E7 3.3V 6 7 D1 DFLS1200 OPT PGND 5 EXTVCC C1 4.7uF 17 3 E8 INTVCC SGND E10 BURST 1 SYNC NC 4 SYNC EXTVCC D JP5 13 14 PGOOD MODE / SYNC 2 6 VOUT C2 0.1uF RUN C 1 5 INTVCC BOOST INTVCC GND INTVCC E9 PGOOD VOUT 4 OPT EXTVCC ON [3] 16 INTVCC 2 3 U1 1 SVIN GND RUN 1 E6 10 E5 CIN3 10uF 50V 1210 PVIN CIN2 10uF 50V 1210 9 + CIN1 OPT 0805 1uF C7 PVIN VIN [2] EXTVCC VIN INTVCC D E11 B JP3 [2] VOUT SELECT VIN VOUT 4.5V - 40V 3.3V / 1A 7V - 40V 5V / 1A CUSTOMER NOTICE [3] VERSION IC A -A LTC3646EMSE -B LTC3646EMSE-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 4 3 N/A SCALE = NONE A HIGH EFFICIENCY LOW QUIESCENT CURRENT STEP-DOWN CONVERTER SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: IC NO. LTC3646EMSE/LTC3646EMSE-1 DEMO CIRCUIT 1820A-A/B 10/04/12 10:31:04 2 SHEET 1 1 REV. 4 OF 1