5 GND CIN2 2.2UF,100V 1812 CIN3 2.2UF,100V 1812 D C1 0.1UF,100V 4 5 6 CCM 5 BURST_EN 6 VFB R5 5.1M 0603 R8 82.5K R6 14.7K 1% R7 130K 1% 5 6 7 8 VOUT RSENSE 15M, 1% VOUT VCC 12 BG 11 4 PGND 10 SENSE+ 9 C5 1UF,16V 0805 D2 1N4148WS Q2 Q4(OPT) Si7370DP +COUT1 1 5 1 6 2 7 3 8 D1 VCC BAS19 C3 680PF 270UF,16V D3 B160 C7 470PF 100V 1206 OSCON 16SP270M COUT2 22UF,16V 1210 X7R COUT3 22UF,16V 1210 X7R GND E3 E4 VOUT [email protected] GND C 2 C C4 120PF 7 VC 8 SENSE- L1 15UH 2 3 SW 14 NC 13 1 2 3 BURST_EN DCM 3 SHDN 4 CSS PULSE PANASONIC PB2020-153 ERJM1WSF15MU Q1 Q3(OPT) Si7850DP 4 2 2 1 R4 200K BOOST 16 TG 15 1 C2 1500PF C6 0.22UF,16V 0603 R2 0 4 JP2 1 VIN 2 NC R3 82.5K 0402 SHDN U1 LT3800EFE 0805 JP1 3 RUN VCC 1 R1 1M 0805 1 E2 SANYO 63MV120AX SGND GND 2 VIN CIN1 120UF, 63V D 3 17 VIN E1 20V-55V 4 5 D5 MBR0520L 1 2 C8 1UF,16V 0603 B Q5B Si1555DL 3 VCC 6 VCC E5 1 D4 MBR0520L Q5A Si1555DL B 1 2 OPTIONAL BOOST BIAS CIRCUIT CUSTOMER NOTICE A NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISITOR ARE IN OHMS, 0402; AND ALL CAPACITORS ARE IN MICROFARAD, 0402. 2. INSTALL SHUNTS ON JP1 PIN 1 & 2, JP2 PIN 3 & 4. 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 CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. CONTRACT NO. APPROVALS DRAWN: TITLE: SCHEMATIC CHECKED: HIGH VOLTAGE SYNCHRONOUS STEP-DOWN CONTROLLER APPROVED: ENGINEER: DAVID C. DESIGNER: 4 3 SIZE A THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 TECHNOLOGY KIM T. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: 2 DWG NO. DC720A-2 * LT3800EFE Friday, March 18, 2005 SHEET 1 REV A 1 OF 1 A