A B C D E REVISION HISTORY ECO REV DESCRIPTION 0 1 Change D1 from 1N4148WT to 1N4148WS DATE APPROVED <DATE> <APPROVED> KSz 05/26/06 4 4 U1 LT1976BEFE E1 VIN 4V-60V R1 200k C1 4.7uF 50V E3 GND E5 SHDN 3 3 4 C5 4700pF 1 2 5 15 SHDN 14 SYNC CSS 9 11 VC BIAS 10 FB 12 C6 100pF C8 1uF 6.3V R4 8.2k BOOST 6 NC SW NC 7 E6 SYNC NC VIN D3 8 CT GND PGFB GND PGOOD 17 16 (Opt) D1 1N4148WS C2 0.33uF 16V C4 0.1uF 16V L1 R6 (Opt) + 33uH CDRH8D28-330NC Sumida D2 10MQ100N C3 100uF 6.3V E4 GND 3 C7 (Opt) R3 0 (Opt) 13 E2 VOUT 3.3V/1A R2 16.5k 1% E10 GND R5 10k 1% R7 (Opt) R8 100k E9 GND E7 PGFB OPTION 2 2 E8 PGOOD APPROVALS 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. 1 A B DRAWN: Rudy Bautista ENGINEER: Keith Sz. APPROVED: Size CHECKED: DCxxxA_00.PCB C 1630 McCARTHY BLVD www.linear.com MILPITAS, CA. 95035 LTC Confidential (408)432-1900 (408)434-0507 (FAX) For Customer Use Only Title High Voltage 1.2A 200kHz Low Ripple Step-Down Regulator xxxA_x.DSN Document Number Date: Sheet D Rev Demo Circuit 977A 1 E of 1 1 1