5 4 3 2 1 D D WDI W/T E3 9 WDI E4 8 W/T R8 0 WDE 7 WDE E5 C JP2 WDE 2 U1 2 C3 10nF 3 W 3 ON T W/T JP1 C4 10nF SYNC SW 3 L1 10uH VOUT C5 22uF 6.3V D1 DFLS140-7 WDO 11 15 SYNC (800KHz) B C2 0.22uF E7 R5 R2 R3 100K 100K 432K E8 C6 10pF RST 10 R4 FB 6 VOUT 3.3V / 700mA C DA 4 OUT 16 14 Rt R1 16.9K BST 1 LT3689EUD 13 Cpor 1 1 (OPT) 12 Cwdt VOUT OFF 95.3K EN/UVLO 5 E2 R7 17 GND GND C1 2.2uF 50V R6 VIN 2 VIN E1 4.5V - 36V Transient to 60V E9 GND RESET 137K E6 E10 WDO B R9 100K 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. A THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 CONTRACT NO. APPROVALS DRAWN HELEN DATE 8/7/09 TECHNOLOGY TITLE LT3689EUD Monolithic 700mA Step - Down Regulator with Power - On Reset and Watchdog Timer CHECKED APPROVED ENGINEER Walker Bai 8/7/09 DESIGNER Friday, August 14, 2009 3 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 SIZE CAGE CODE SCALE: DWG NO FILENAME: 2 REV A DC1312A SHEET 1 1 OF 1 A