5 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 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 Applications Engineering for assistance. ECO REV DESCRIPTION DATE 3 PRODUCTION 11/05/08 R.YING 10/01/09 R.YING 09/24/10 DING L. 1 3.1 2 3.2 IC CHANGE, PART VALUE CHANGES PART VALUE CHANGE, C22, R31 APPROVED INTVCC D D MODE/PLLIN VIN CCM BURST P.S. CIN4 OPT R46 1% E4 MODE/PLLIN JP1 OFF 1 3 C22 TG 4 BG 2 3 7 8 1K 10nF SW VIN 3 Q1 RJK0305DPB CIN3 22uF 25V R47 C20 1nF VIN 2 JP2 E1 4.5V - 14V + CIN1 150uF 16V 5 ON 1 97.6K 1% R31 2 RUN EXTCLK 1 350K VIN J1 FREQ/PLLFLTR R30 E5 VIN 5 6 200K Q5 OPT Si4816BDY 5 JP3 3 INTVCC 4 2 1 TG 4 CIN6 22uF 25V CIN5 OPT J2 CIN7 OPT GND E6 4 GND OPT RUN Q2 OPT 1 2 3 OPT 1 2 3 R48 C23 OPT C VOUT SW 3 4 OPT 7 ILIM R41 0 COUT3 47uF 6.3V 4 INTVCC ILIM + COUT2 330uF 2.5V GND E8 BG 10 1.5V / 15A J4 OPTIONAL DCR SENSING 9 GND R27 OPT INTVCC C27 2.2uF 10V + COUT1 330uF 2.5V Q4 OPT VIN 2.2 5 14 15 13 TG SW 5 4 VOUT 0.002 OHM FB 8 VOUT 16 C19 1uF BG R39 43.2K 1% 11 SENSE+ C32 OPT VIN R37 Q3 RJK0329DPB C31 4.7uF 10V 6 C29 2 CMDSH-3 ITH GND R38 49.9K 1% TK/SS D2 1 0 J3 RSNSE INTVCC R36 12 VOUT 0.4uH 1 2 3 2 OPT BOOST SENSE- 470pF C25 0.1uF 10V 1 2 3 R35 RUN GND R40 6.49K 1% 1 0.1uF 10V C28 5 3300pF MODE/PLLIN C24 C26 L1 FREQ/PLLFLTR U1 [1] C E7 R32 0 TRK/SS 17 E2 R29 OPT C18 OPT C30 B B E9 1nF [1] R1 OPT INTVCC R42 R43 [1] OPT R44 R45 OPT OPT R10 100 R9 100 [1] A ASSY U1 R42 E9 -A LTC3851AEUD OPT ISET -B LTC3851AEUD-1 100K UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCE ON ANGLE - - 2 PLACES - - - 3 PLACES - - INTERPRET DIM AND TOL PER ASME Y14.5M -1994 PGOOD THIRD ANGLE PROJECTION CONTRACT NO. APPROVALS DRAWN MI CHECKED DATE 05/16/08 DING L. 09/24/10 APPROVED ENGINEER TECHNOLOGY SCH, LTC3851AEUD/LTC3851AEUD-1, SYNCHRONOUS BUCK CONVERTER CAGE CODE DWG NO 5 4 3 Friday, September 24, 2010 SCALE:NONE 2 REV DC1432A Custom DO NOT SCALE DRAWING A TITLE SIZE DESIGNER 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 FILENAME: 1432A-3.dsn SHEET 1 3.2 1 OF 1