5 4 3 2 1 REVISION HISTORY ECO FB1 DESCRIPTION DATE APPROVED 4 PROD 06/26/12 EDWIN L. L6 FERRITE BEAD C10 OPT REV OPT C11 OPT C9 OPT + U1 LT3504EUFD D D 25 OPTIONAL CIRCUIT 24 C5 2.2uF E1 VIN VIN 5.4V - 40V C8 22uF 50V C19 1uF C27 1uF C26 1uF C20 OPT 50V 50V 50V 50V 50V C28 OPT 50V 50V 11 26 28 DA1 VIN VIN FB1 VOUT1 R8 100k C E11 PG FB2 3 2 1 ON E14 RUN/SS2 DA2 RUN/SS1 JP2 10V EN/UVLO R6 200K 23 SW3 RUN/SS1 DA3 3 RUN/SS2 14 OFF 15 ON E13 SW4 MBRM140T3G R2 31.6k C22 43pF FB4 50V GND R10 C 10.2k 1% 3 E7 L3 4.2uH 4 MBRM140T3G VOUT3 R3 21.5k C23 82pF 1% C14 C3 22uF 0.1uF 50V 6.3V 2.5V / 1A E8 GND R11 21 10.2k 1% 8 E9 L4 4.2uH 7 MBRM140T3G VOUT4 R4 12.7k C24 100pF 1% C4 C15 22uF 0.1uF 6.3V 50V 1.8V / 1A E10 GND B R12 19 10.2k 1% GND RT/SYNC 6.3V 3.3V / 1A E6 29 RUN/SS4 DA4 GND 1% (1MHz) RUN/SS4 C2 C13 10uF 0.1uF 1% D4 GND R5 18.2k GND VOUT2 22 RUN/SS3 27 17 3 2 1 JP5 10V 1 3 2 OFF RUN/SS4 C18 47nF RUN/SS2 GND ON E16 RUN/SS4 12 RUN/SS3 5V / 1A E4 E5 RUN/SS1 18 10V JP4 C17 47nF 1 RUN/SS3 FB3 10 ON E15 RUN/SS3 2 1 JP3 10V 50V L2 8.2uH 2 D3 OFF 13 6.3V 10.2k 1% PG RUN/SS2 C16 47nF C1 C12 10uF 0.1uF VOUT1 R9 20 PG RUN/SS C7 47nF 16 JP1 1% E12 RUN/SS1 SW2 1 C21 22pF 1% D2 2 OFF MBRM140T3G R1 53.6k E3 VIN VIN GND 6 VOUT1 VIN EN/UVLO R7 1% 3 475k ON E2 B C25 OPT L1 8.2uH 5 D1 9 C6 1uF SW1 SW5 L5 10uH 6.3V + SKY OFF SYNC SYNC 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 3 APPROVALS PCB DES. APP ENG. TECHNOLOGY MI EDWIN L. TITLE: SCHEMATIC 40V QUAD BUCK REGULATOR SIZE N/A SCALE = NONE 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only IC NO. LT3504EUFD REV. DEMO CIRCUIT 1207A DATE: 06/26/12 14:30:03 SHEET 1 1 4 OF 1 A