1 R6 5.1M R14 (OPT) R9 R8 16.2K 1% SYNC BG 12 6 VC R7 20K C7 2200pF C6 100pF SENSE+ 10 8 FSET SENSE- 9 8 7 6 5 8 7 6 5 4 4 1 2 3 Q1 Si7370DP Q4 Si7370DP (OPT) VOUT VCC C5 1uF 16V VOUT E9 VCC L1 D8 B120 (OPT) PGND 11 7 SYNC R10 49.9K D1 BAS521 R5 0 VCC 13 5 VFB (OPT) 143K 1% SW 14 4 BURST_EN C12 0 1 2 3 3 SS VFB R4 R15 0 4 BG D3 1N4148WS-7 Q5 Si7370DP (OPT) 4 Q2 Si7370DP 15uH R11 0.01 C4 470pF 50V VOUT + COUT1 + COUT2 68uF 68uF 16V 16V 1 6 BURST 1500pF 0.1uF 16V D2 B160 COUT3 22uF 16V VOUT [email protected] E3 COUT4 1uF 16V 2 5 C3 C2 8 7 6 5 2 CONT . 4 PULSE SKIP TG 15 2 SHDN R3 82.5K R2 0 GND E4 1 2 3 3 1 BOOST 16 8 7 6 5 VFB JP2 MODE 1 VIN 100V 1 ON OFF 0.47uF LT3845EFE 1 2 3 C1 JP1 RUN 2 U1 2 E8 A R1 1M 1 VCC CIN3 2.2uF 100V E2 3 GND CIN2 2.2uF 100V 2 CIN1 47uF 63V 1 + 1 GND VIN E1 2 VIN 20V - 55V A E7 17 SGND VIN 2 GND E10 C13 (OPT) E5 R18 100K B B 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 1 CONTRACT NO. APPROVALS DRAWN HELEN DATE 3/08/06 CHECKED TECHNOLOGY TITLE LT3845EFE, High Voltage Synchronous Buck Controller with Programmable Frequency and Sync SIZE CAGE CODE APPROVED ENGINEER Kevin Huang 3/08/06 DESIGNER Tuesday, January 23, 2007 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 SCALE: FILENAME: DWG NO REV A DC1073A SHEET 1 OF 2 1 2 A A OPTIONAL BIAS CIRCUIT VCC VOUT R13 (OPT) 4 R12 (OPT) Q3B Si1555DL C10 1uF 10V 3 BG C11 1uF 10V 6 1 Q3A Si1555DL 2 1 C9 1uF 10V 2 D5 BAV99 3 C8 1uF 10V 1 2VOUT 2 3 3VOUT 5 D4 BAV99 B B 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 1 CONTRACT NO. APPROVALS DRAWN HELEN DATE 3/08/06 CHECKED TECHNOLOGY TITLE LT3845EFE, High Voltage Synchronous Buck Controller with Programmable Frequency and Sync SIZE CAGE CODE APPROVED ENGINEER Kevin Huang 3/08/06 DESIGNER Tuesday, January 23, 2007 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 SCALE: FILENAME: DWG NO REV A DC1073A SHEET 2 OF 2