5 4 3 2 1 REVISION HISTORY INPUT MODE 1 ECO REV SINGLE DESCRIPTION 2 PRODUCTION DATE APPROVED 01-17-12 EDWIN L. 2 VOUT1 CASCADE 3 4 VIN1 D DUAL JP1 [1] VIN2 D VIN1 TP1 C22 2.2uF VIN1 100V 1210 0603 35 TP3 6 D7 OPT 38 D1 C4 0.47uF 0603 MMSD701T1G D2 B360B 2 TP5 GND C6 10uF 16V OPT 0805 4 C7 100uF 10V 1210 9 R5 42.2K 1% R7 100K C10 8 22pF 7 34 TP7 33 R9 8.06K 1% CMPO1 SS1 32 TP9 30 TP11 R11 100K 1% C12 27 C14 680pF R13 30k 1% 0.1uF 1 3 C16 33pF 5 10 B SYNC 15 TP13 C25 10nF OPT R15 7.32k 1% R16 20k 1% BST1 BST2 SW1 SW2 IND1 IND2 VOUT1 VOUT2 FB1 FB2 CMPI1 CMPI2 CMPO1 CMPO2 SS1 SS2 ILIM1 ILIM2 VC1 VC2 RT/SYNC CLKOUT DIV TJ NC NC NC NC NC NC NC NC NC 7V - 60V TP17 0603 TP4 SHDN2 D8 OPT 20 C5 0.47uF 0603 D4 D5 MMSD701T1G B360B C 18 VOUT2 16 C8 100uF 10V 1210 11 C11 22pF 12 13 R6 24.9K 1% R8 100K C9 10uF 16V OPT 0805 TP6 24 TP8 25 VOUT2 3.3V / 2A * GND R10 8.06K 1% 26 TP10 29 R12 100K 1% 28 R14 30k 1% C15 680pF 37 31 TP12 C13 CMPO2 SS2 0.1uF C17 33pF 21 19 R18 17 TP14 OPT TP15 CLKOUT B TEMP R17 40.2k 1% L3 22uH OPT OPT C20 2.2uF 100V OPT 1210 + C18 22uF 100V OPT OPTIONAL CIRCUIT 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 NOTES: UNLESS OTHERWISE SPECIFIED, [1] SEE QUICK START GUIDE FOR DETAILS ON JP1 SETTING AND INPUT VOLTAGE IMPLEMENTATION ORDER. 2. ALL CAPACITORS ARE 0402. ALL RESISTORS ARE 0402. SEE QUICK START GUIDE FOR DETAILS ON CURRENT CAPABILITY. APPROVALS PCB DES. APP ENG. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 4 3 TECHNOLOGY JW 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only EDWIN L. TITLE: SCHEMATIC SIZE * 5 VIN2 VIN1 FB1 BEAD C19 0.01uF 100V OPT 0603 NC R2 1k 1% 14 C24 10nF (300kHz) VIN1 C3 2.2uF 100V 1210 TP16 C21 22uF 100V 23 L2 10uH VOUT1 * SHDN2 L1 22uH C VOUT1 5V / 2A SHDN1 D3 MMSD701T1G OPT 22 LT3992EFE SHDN1 C23 2.2uF 100V 1210 VIN2 + GND U1 D6 MMSD701T1G OPT VIN2 R1 1k 1% TP2 VOUT1 PGND GND VOUT2 39 C2 2.2uF 100V 1210 22uF 100V 36 7V - 60V VIN1 + C1 N/A SCALE = NONE 2 DUAL MONOLITHIC STEP-DOWN CONVERTER IC NO. LT3992EFE DEMO CIRCUIT 1537A DATE: Tuesday, January 31, 2012 SHEET 1 1 REV. 2 OF 1 A