5 4 3 2 1 D D VIN E1 VIN 36V to 72V L1 22µH XAL6060-223MEC Coilcraft C2 4.7µF 100V 1210 + C1 E2 47µF 80V C3 4.7µF 100V 1210 C4 4.7µF 100V 1210 D1 SMBJ85A-13-F R1 100 1210 D2 CMMR1U-02 C5 120pF 250V 0805 GND C6 1µF 100V 0805 U2 LT3748EMS INTVCC 5 R4 51k RFB 10 12 C14 0.22uF 11 R10 60.4k 1% 14 C15 470pF SS GATE TC 68 0805 C13 4.7µF 16V 0805 RREF SENSE GND GND 8 9 11 C7 47µF 16V 1210 6 1 5 BAV20W-7-F Coilcraft C9 47µF 16V 1210 C8 47µF 16V 1210 VOUT+ 12V / 5A C12 47µF 16V 1210 D3 CMZ5928B R2 (Opt) 1206 Q1 BSC047N08NS3 7 C VOUTR6 0 Ohm R8 160k 1% 0805 U1 LT8309ES5 Q2 BSC320N20NS3G D5 R11 7 3 Ohm C18 47pF R9 4 BAV20W-7-F 3 Ohm 0805 D6 36V R13 0.010 1% 0815 C20 4700pF 250V 1812 CUSTOMER NOTICE NOTE: UNLESS OTHERWISE SPECIFIED. 1. ALL RESISTORS 0603. 2. ALL CAPACITORS 0603. R15 3 INTVCC GND 5 2.37k 1% 1206 DRAIN GATE 3 2 C17 4.7uF 25V 0805 1 C21 (Opt) 0805 B APPROVALS TECHNOLOGY TITLE: SCHEMATIC N/A SCALE = NONE 2 1630 McCarthy Blvd. Milpitas, CA 95035 www.linear.com Phone: (408)432-1900 Fax: (408)434-0507 A LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY SIZE C:\PADS PROJECTS\1961A(LT8309MSE)\SCH\1961A_REV2.DSN THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. VIN C16 1uF 100V 1206 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. A 4 C11 47µF 16V 1210 E3 E4 8 6 B 5 C10 47µF 16V 1210 9 0 Ohm R14 6.04k 1% VOUT R7 16 VC R12 7.50k 1% C19 33nF D4 R5 EN/UVLO 4 2 INTVCC VIN 3 12 10 1 R3 1.2M C L2 1µH XAL6030-102MEC T1 PA1736NL 3 DATE: IC NO. 60W, 36V-72VIN TO 12V/5A SYNCHRONOUS FLYBACK CONVERTER REV. LT8309ES5/LT3748EMS 2 DEMO CIRCUIT 1961A Feb 21, 2014 07:32:08 SHEET 1 1 OF 1