A B C D E REVISION HISTORY ECO REV DESCRIPTION 1 DATE APPROVED MOLLY Z. 04/29/10 PRODUCTION 4 4 VIN 6.5V - 62V L1 33uH LPS6225-333ML VIN C2 0.22uF 16V 0603 VIN E3 6 + E4 3 U1 LT3990EMSE C4 10uF 100V C3 2.2uF 100V 1210 14 4 GND 3 5 7 10 12 15 VOUT R6 100K 0402 E6 SW PG BOOST EN/UVLO BD NC NC NC NC NC NC FB FB RT 11 R1 1.00M 1% C1 22uF 10V 1206 C5 22pF E1 VOUT 5V / 350mA E2 GND 13 3 1 2 R2 316K 1% 16 R5 374K 1% 0402 (400kHz) GND GND 8 PG 9 VOUT 17 E5 EN/UVLO VIN 2 1 ON 2 2 R8 (Opt) 3 OFF JP1 R7 (Opt) 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. 1 TECHNOLOGY RB MOLLY Z. LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY TITLE: SCHEMATIC THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. A B C IC NO. DATE: REV. LT3990EMSE/LT3990IMSE DEMO CIRCUIT 1471A N/A SCALE = NONE 1 62V 350mA STEP-DOWN REGULATOR WITH 2.5uA QUIESCENT CURRENT AND INTEGRATED DIODES SIZE C:\PADS PROJECTS\1471A\SCH\1471A_REV1.DSN 1630 McCarthy Blvd. Milpitas, CA 95035 www.linear.com Phone: (408)432-1900 Fax: (408)434-0507 Thursday, May 13, 2010 SHEET D E 1 1 OF 1