4 3 2 1 REVISION HISTORY This circuit is proprietary to Linear Technology and supplied for use with Linear Technology parts. Customer Notice:Linear Technology has made a best effort to design a circuit that meets customer-supplied specifications; however, it remains the customers 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 Applications Engineering for assistance. E1 VIN 15V-60V ECO REV - 0 DESCRIPTION DATE PROTOTYPE (974A_09.PCB/97A_REV0.DSN) APPROVED - 09/08/05 VIN + CIN2 2.2uF 100V R1 1M 0805 GND E2 GND B CIN1 68uF 63V B JP1 VOUT 1 ON 2 U1 LT3844EFE VIN 2 SHDN 3 2 BURST 1 0.01uF VFB 3 R6 1M 0603 VC R7 14.7K 1% R14 (Opt) R8 130K 1% R9 82.5K 1% C12 (Opt) BOOST 16 TG 15 SS SW 4 BURST_EN 5 VFB 6 VC 7 SYNC 8 RT VCC 13 PGND 12 Sgnd Q1 Si7852DP 0 Ohm R16 VOUT L1 SW 10 R5 15uH IHLP-5050EZ-01-15uH-M VCC D1 BAS19 C4 0.1uF 10% 9 C5 1uF 16V E3 VOUT 12V @ 4.2A VOUT 0.015 1% + D2 PDS5100H SENSE+ 11 SENSE- 10 C6 120pF R15 49.9K 1% C7 680pF 14 C2 0.22uF 16V COUT1 180uF 16V COUT2 10uF 16V GND E4 GND 2 JP2 VCC MODE FIXED 1 R2 Sgnd C3 3 C1 1000pF 100V 1 R3 113K 1% VIN 3 17 OFF D5 1N4148WS SEE NOTE (1) E6 SYNC A NOTES: 1. If the SYNC function is not being used tie the Sync pin to ground. OPTIONAL BOOST BIAS CIRCUIT (DO NOT INSTALL) VCC R10 L2 0 Ohm 10UH ZHCS400 C9 1uF 16V C10 220pF R11 107K 1% R12 10K R13 12.4K 1% A VOUT D3 1 D4 ZHCS400 (Opt) C8 4.7UF,6.3V 0805 5 SW 3 VCC E5 VBIAS 9V-20V (Opt) VIN FB SHDN GND 4 U2 LT1613CS5 + 2 C11 22uF 35V (Opt) LTC CONFIDENTIAL - For Customer Use Only UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCE ON ANGLE - - 2 PLACES - - - 3 PLACES - - INTERPRET DIM AND TOL PER ASME Y14.5M -1994 DRAWN RB 08/24/05 THIRD ANGLE PROJECTION CHECKED - - CONTRACT NO. APPROVALS APPROVED - - ENGINEER D. CANNY 08/24/05 DESIGNER - 3 - Tuesday, February 21, 2006 DO NOT SCALE DRAWING 4 DATE 2 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 TITLE SCH, HIGH VOLTAGE STEP-DOWN CONTROLLER SIZE CAGE CODE SCALE: NONE DWG NO REV DEMO CIRCUIT 974A FILENAME: 974A_Rev1.DSN/PCB SHEET 1 1 1 OF 1