5 4 3 2 1 REVISION HISTORY ECO REV __ DESCRIPTION 1 PRODUCTION APPROVED DATE JAINO P. 7-11-11 D D 27 R2 8 21 RST1 RST2 CWDT 3 RST2 SS2 11 E9 E10 C7 C8 1500pF 1500pF B SYNC VOUT1 E2 E3 VOUT1 5V @ 1A GND 24 25 L2 1.0uH 6 C4 22uF 6.3V 1206 R3 100K 1 5 R5 100K 28 4 R7 49.9K C5 1000pF E5 VOUT2 1.8V @ 0.8A E7 GND E8 SYNC C C6 1000pF GND 100K WDE GND R8 WDE R1 301K 18 R10 100K 17 9 16 100K GND ON VOUT1R6 SS1 GND 1 OFF JP1 2 FB2 WDO 15 10 GND 100K 23 R4 E15 FB1 26 E13 SW2 WDI GND E6 13 RST1 VIN2 RT GND PGOOD2 29 WDO DA E12 14 C3 22uF 6.3V 1206 D2 EN2 CPOR WDI U1 7 C 19 LT3641EFE 100K 2 PGOOD2 EN/UVLO L1 4.7uH SW1 1 R13 (OPT) 2 2 R11 100K 3 1 BST (OPT) E4 VOUT1 20 VIN VOUT1 SW E11 22 R12 301K R14 EN2 C2 4.7uF 50V 1206 12 GND D1 C1 0.22uF 10V VIN VIN E1 7V -42V TRANSIENT TO 55V R9 32.4K B OPTIONAL COMPONENTS L3 LPS4018-332ML FB1 VEMI GND E14 VIN OPT C10 (OPT) 0603 + C9 22uF 63V OPT C11 (OPT) 1210 E16 NOTE: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE IN 0603. ALL CAPACITORS ARE IN 0603. A 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 CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 2. INSTALL SHUNTS AS SHOWN. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 APPROVALS PCB DES. APP ENG. TECHNOLOGY HZ JAINO P. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: SCHEMATIC DUAL MONOLITHIC STEP-DOWN SWITCHING REGULATOR WITH POWER-ON RESET AND WATCH DOG TIMER SIZE N/A SCALE = NONE 2 DATE: IC NO. LT3641EFE DEMO CIRCUIT 1727A Friday, October 28, 2011 SHEET 1 1 REV. 1 OF 1 A