5 4 3 2 1 REVISION HISTORY U1 LT3973EMSE VIN E3 5.6V - 42V GND VIN 4 + C4 9 C3 2.2uF 50V 1206 10uF 50V E4 3 2 5 SW PG BOOST EN/UVLO BD OUT FB GND C PG EN/UVLO APPROVED DATE JAINO P. 09-06-11 PRODUCTION RT 7 C2 0.22uF 8 R1 1.00M 1% 1 10 E1 VOUT C1 22uF 6.3V 1206 C5 10pF VOUT 5V / 750mA E2 GND R5 215k 1% (600kHz) R2 316k 1% C R9 200K E6 E5 JP1 ON OFF 1 2 3 R7 OPT R8 OPT B B CUSTOMER NOTICE NOTES: UNLESS OTHERWISE SPECIFIED A 2 DESCRIPTION L1 15uH 6 11 SUNCON 50CE10BSS REV _ D VIN GND D ECO 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0402. 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 TECHNOLOGY KIM T. JAINO P. TITLE: SCHEMATIC A 42V, 750mA, MICROPOWER BUCK REGULATOR SIZE IC NO. DATE: REV. LT3973EMSE N/A SCALE = NONE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only 2 DEMO CIRCUIT 1730A 09/06/2011, 10:10 AM SHEET 1 2 1 OF 1