5 4 3 2 1 SHOULD BE PLACED BETWEEN VIN1 AND GND1. C12 ** C2 SHOULD BE PLACED BETWEEN VIN2 AND GND2. THESE CAPACITORS MUST BE PLACED AS CLOSE AS POSSIBLE TO LT8640. EN/UV SYNC E1 R1 100K E2 C11 10uF 50V 1206 22uF 63V R6 OPT SUNCON 63CE22BS ** 13 C12 1uF 50V ** 14 E6 17 JP1 E5 SYNC BURST C SPREAD-SPECTRUM PULSE-SKIPPING GND + C1 C2 1uF 50V 1 2 3 4 5 6 7 8 2 16 C7 1uF 25V 15 R2 18.2K (2MHz) E9 TR/SS E7 C8 0.1uF VIN2 BST 3 L1 C4 1.5uH 0.1uF 16V 74437346015 8 SW 9 SW 21 SW 22 SW EN/UV SYNC BIAS RT PG FB C6 100uF 10V 1210 R7 1 0 E4 R3 19 R4 20 R5 243k C5 C9 1uF E3 C13 4.7uF VOUT 5V / 5A * GND C 100k 1Meg 10pF PG L2 0 B VIN VEMI E10 C14 0.1uF 50V 0402 C3 10uF 50V 1210 C10 10uF 50V 1210 2010 CUSTOMER NOTICE LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; TECHNOLOGY HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED TITLE: SCHEMATIC CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. NOTES: UNLESS OTHERWISE SPECIFIED A SEE DEMO MANUAL VOUT INTVCC TR/SS * E8 FB1 74279226101 B D VIN1 GND GND 4 VIN 18 VIN 5.7V - 42V 6 7 GND1 10 GND1 11 GND2 GND2 D U1 LT8640EUDC 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 N/A DATE: 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only A 42V, 5A MICROPOWER SYNCHRONOUS STEP-DOWN SILENT SWITCHER IC NO. REV. LT8640EUDC 3 DEMO CIRCUIT 2202A Thursday, November 20, 2014 2 SHEET 1 1 OF 1