4 3 OPTIONAL CIRCUIT C9 0.01UF 0603 L1 6.8UH D + C11 U1 LT3972EMSE 22UF,63V SANYO 63CE22BS D1 MBRA340T3 2 1 C1 0.47UF 1 2 3 4 + C2 C3 4.7UF,50V 1210 22UF,63V SANYO 63CE22BS 5 R1 63.4K RT 10 VC 9 BD BOOST R2 110K FB 8 PGOOD 7 SW VIN RUN/SS R3 590K SYNC 6 R4 100K 11 C VIN E1 6.3V - 33V TRANSIENT TO 62V E8 GND E2 GND C10 4.7UF,50V 1210 C8 100PF RUN SHDN EXTSS EXTSS JP1 1 2 3 4 C7 0.22UF,50V 0805 CUSTOMER NOTICE NOTES: UNLESS OTHERWISE SPECIFIED 2. INSTALL SHUNT ON JP1 AND JP2 PINS 1&2. C5 0.1UF 50V 0603 E6 R5 15K E7 C6 1000PF 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. 4 JP2 BURST MODE SYNC ON 1 2 3 E9 CONTRACT NO. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 C4 47UF,10V 1206 E3 B A E5 VOUT R6 100K E4 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0402. 1 VISHAY IHLP-2525CZ-01 TAIYO YUDEN VISHAY FB MJ3216HS800 IHLP-2525CZ-01 L2 FB1 10UH BEAD D 2 GND 5 3 APPROVALS DRAWN: TECHNOLOGY KIM T. CHECKED: TITLE: SCHEMATIC SIZE DWG NO. APPROVED: ENGINEER: KEVIN H. DESIGNER: A DATE: VOUT [email protected] C GND PGOOD GND 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only 3.5A, 33V STEP-DOWN SWITCHING REGULATOR WITH SYNC FUNCTION DC1458A * LT3972EMSE Wednesday, September 10, 2008 2 B SYNC SHEET 1 A REV A 1 OF 1