5 4 3 2 1 REVISION HISTORY ECO REV 1 2 DESCRIPTION APPROVED DATE T. ZHOU 10-06-09 PRODUCTION D D U1 LT3686EDD VIN BD 10uF 63V SANYO 63CE10BS E3 C3 2.2uF 50V 1206 R2 100K JP1 ON OFF GND 6 1 2 3 4 R4 38.3K C 7 C4 0.01uF 5 E5 VIN BOOST EN/UVLO SS SW 10 C1 0.22uF L1 16V 6.8uH MODE RT DA MODE R1 10K 8 1 1 +C2 2 GND R7 61.9K (1MHz) FB 9 VOUT E2 VISHAY IHLP-2020BZ D2 MBRM140T1G C5 22pF R3 31.6K 2 E1 VIN 5V - 37V 55V TRANSIENT C6 22uF 10V 1206 3 VOUT 3.3V/1.2A C E4 GND R6 10K 11 B B NOTE: UNLESS OTHERWISE SPECIFIED A 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0402. CUSTOMER NOTICE CONTRACT NO. LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A APPROVALS CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. K. TRAN VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL T. ZHOU 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. 5 4 3 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: SCHEMATIC SIZE A DATE: A 37V, 1.2A BUCK REGULATOR IC NO. LT3686EDD DEMO CIRCUIT 1323A Tuesday, October 06, 2009 2 SHEET 1 REV 2 1 OF 1