1 2 3 4 5 6 7 8 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 3 DATE PROTO APPROVED 11/04/.08 INTVCC OPTIONAL DCR SENSING: R1 200K A NOTE: WHEN DCR SENSING IS IMPLEMENTED, SHORT R10 AND R17, DO NOT STUFF R8,R9,R20 AND R21 A E1 PGOOD1 TRACK1 JP5 E10 SS TRACK R2 3 TRACK1 VOUT2 C2 10pF 1 2 35.7K R26 R3 11.5K VOUT1 C1 0.1uF OPT R4 57.6K 1% R5 R6 182K 1% 0 C3 22pF MODE R8 0 JP2 1 2 CCM 3 4 PULSE SKIP 5 6 BURST MODE R11 8.2K C4 U1 E4 SNS1- VIN VIN R34 OPT JP3 ON 1 2 ON 1 2 OFF 3 OFF 3 C R36 OPT C14 SW1 25 24 6 PLLIN/MODE BG1 23 7 SGND VIN 22 8 RUN1 PGND 21 RUN2 EXTVCC SNS2+ 11 12 R16 15K C15 13 C28 OPT 1% R37 [1] INTVCC 3300pF 14 C29 E2 SNS2- INTVCC SNS2+ BG2 VFB2 BOOST2 ITH2 SW2 TRACK/SS2 TG2 1 2 3 2.2 CMDSH-4E C11 VIN 4.7uF 20 EXTVCC * 10V 19 0.1uF BG2 SHT 2 4 D3 17 R15 16 C16 2.2 0.1uF Q3 BSZ097N04LS E3 R19 976K 1% 4.7uF 50V 4.7uF 50V R32 OPT J4 GND GND C R33 OPT E13 Q4 BSZ097N04LS VOUT2 L2 7.2uH J5 VOUT2 CDEP105-7R2M SW2 SHT 2 R20 0 VIN 4.5V - 36V E6 0.008 OPT R22 C7 SNS2+ 1 2 3 R18 102K 1% C17 OPT CMDSH-4E TG2 SHT 2 VIN SNS2- VIN INTVCC J3 R31 INTVCC 18 15 OPTIONAL DCR SENSING C13 + 47uF 50V C12 VIN SNS1+ OPTIONAL DCR SENSING C27 EXTVCC C20 10uF 16V COUT2 + 68uF 10V COUT4 + OPT J6 R21 0 VOUT2 8.5V / 3A GND [2] E14 GND VOUT2 VOUT2 * EXTVCC C21 C22 4.7uF 10V OPT R23 0 0 TRACK2 CONTRACT NO. JP6 R24 TRACK 3 TRACK2 97.6K1% ASSY -A U1 R35 R37 LTC3857EGN-1 OPT OPT SS 2 E15 [1] GND R17 1000pF 2.2uF D 0 GND E5 4 INTVCC C19 J2 SNS1- 4 R14 C18 OPT BG1 SHT 2 INTVCC B E12 OPT D2 R13 VOUT1 3.3V / 5A R30 BOOST1 47pF + COUT3 OPT R29 OPT Q2 BSZ097N04LS 0.1uF FREQ 9 R28 OPT 26 SNS1- SNS2- 10 R35 [1] TG1 BSZ097N04LS + COUT1 220uF 4V C10 27 5 JP4 RUN2 RUN1 PGOOD1 SNS1+ 28 4 0 PLLIN / MODE VFB1 100uF 6.3V 5 6 7 8 3 4 TRACK/SS1 C5 1 2 3 SNS1+ ITH1 Q1 1 2 3 2 R7 TG1 SHT 2 [1] 1 0.005 5 6 7 8 1000pF 5 6 7 8 4700pF R38 OPT J1 VOUT1 INTVCC SGND VOUT1 R10 C6 OPT E9 L1 3.2uH CDEP105-3R2M C26 1% 100K SW1 SHT 2 VIN R27 B E11 R9 0 5 6 7 8 INTVCC APPROVALS 1 DRAWN MI C23 R25 10K 1% CHECKED 0.1uF APPROVED ENGINEER DESIGNER DATE 10/26/07 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 D TITLE SCH, LTC3857EGN-1 / LTC3858EGN-1, LOW QUIESCENT CURRENT DUAL OUTPUT SYNCHRONOUS BUCK CONVERTER SIZE CAGE CODE DWG NO REV 3 DC1352A - A / B -B LTC3858EGN-1 1 66.5K 12.7K 2 * (14V MAX) [2] FOR REGULATION VIN > 9V 3 Wednesday, July 22,2009 4 5 6 SCALE: NONE FILENAME: 1352A-3.DSN 7 SHEET 1 8 OF 2 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. REVISION HISTORY ECO VIN REV DESCRIPTION 3 C24 C25 OPT OPT DATE PROTO APPROVED 11/04/08 5 6 7 8 VIN Q5 OPT 4 1 2 3 TG1 5 6 7 8 SW1 Q6 OPT 4 1 2 3 BG1 VIN 5 6 7 8 SHT 1 Q7 OPT 4 1 2 3 TG2 5 6 7 8 SW2 Q8 4 OPT 1 2 3 BG2 5 6 7 8 VIN Q1X 4 OPT 1 2 3 TG1 5 6 7 8 SW1 X6 1 1 X5 X7 1 1 1 X1 1 X2 Represents Tooling Holes 4 REPRESENTS STAND OFFS 1 2 3 BG1 Q2X OPT X4 on PCB VIN 5 6 7 8 SHT 1 1 2 3 DRAWN MI DATE 10/26/07 CHECKED 5 6 7 8 SW2 APPROVED Q4X OPT 4 1 2 3 BG2 CONTRACT NO. APPROVALS 4 TG2 Q3X OPT TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 TITLE SCH, LTC3857EGN-1 / LTC3858EGN-1, LOW QUIESCENT CURRENT DUAL OUTPUT SYNCHRONOUS BUCK CONVERTER ENGINEER DESIGNER SIZE CAGE CODE DWG NO REV 3 DC1352A - A / B Wednesday, July 22, 2009 SCALE: NONE FILENAME: 1352A-2.DSN SHEET 2 OF 2