5 4 3 2 1 D D L1 4.7uH VISHAY 1HLP2525CZER4R7M01 C6 22uF,10V U1 LT1938EDD 4.5V - 25V E1 + GND C5 10uF,35V C4 22uF,50V SANYO 50CV22BS VIN E3 BD RT 10 9 2 BOOST VC 3 SW FB 4 VIN BIAS 7 PGOOD 6 5 RUN/SS 1 RUN 2 SHDN 3 EXTSS R1 60.4K R5 19.1K E4 C8 680pF VOUT 3.3V @ 2.2A GND C 8 R3 165K R2 102K R4 100K 11 VIN C1 0.47uF GND D1 DFLS230L 2 1 C 1 C7 1uF 10V E2 R6 100K E5 PGOOD C9 0.1uF,50V 4 JP1 B B EXTSS GND E8 E7 CUSTOMER NOTICE LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. A CONTRACT NO. APPROVALS TITLE: CHECKED: APPROVED: ENGINEER: KEVIN H. DESIGNER: 4 3 SIZE DATE: 2 LT1938EDD 2.2A, 25V Step-Down Switching Regulator A THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 TECHNOLOGY DRAWN: Antonina K 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only DWG NO. REV DC1273A A Friday, June 29, 2007 SHEET 1 1 OF 1 A