5 4 3 2 1 REVISION HISTORY ECO REV DESCRIPTION 0 DATE PROTO APPROVED xx/xx/07 INTVCC MODE 1 PULSE SKIP 2 BURST MODE/SYNC VIN FORCED CONTINUOUS E7 MODE 3 INTVCC 4 VIN JP4 R40 R48 10.0K 1% SYNC 0 E9 E11 INTVCC R41 (Opt) R47 3.16K 1% 1 RUN1 2 RUN2 R43 (Opt) 1 RUN2 3 OFF R44 (Opt) C42 (Opt) JP2 R1 43.2K 1% R38 0 1 TK/SS3 2 9 R3 24.9K 1% VIN E13 RUN3 R2 20K 1% C2 (Opt) R45 (Opt) RUN3 C1 10pF 40 TK/SS2 VOUT2 2 TK/SS2 10 220pF 12 SW1 BG1 VFB1 ITH1 TG2 VFB2 BG2 R8 INTVCC C44 (Opt) R6 20K 1% TG3 PGOOD12 BG3 SENSE3- PGOOD3 SW3 SENSE3+ 16 220pF R9 CMDSH-3 TG1 D2 R28 25 C25 0.1uF 0 CMDSH-3 27 SW2 28 INTVCC 56 22 S2N Q3B Si4816BDY BG2 4 R10 2.2 VOUT2 E3 RSNS2 7 29 C11 4.7uF 16V 0805 S2P L2 1.5uH RLF7030T-1R5N6R1 0.008 5% R54 (Opt) COUT3 22uF 6.3V X5R R56 (Opt) + COUT4 220uF 4V 4TPE220MF GND R55 24 D3 R29 18 C26 0.1uF 0 CMDSH-3 (Opt) C10 0.1uF 25V SENS2N SENS2P TG2 19 20 SW2 BG2 VIN BG2 21 CIN5 4.7uF 25V 8 C21 C22 C23 1000pF 1000pF 1000pF SENS3N SW3 R26 S3P S3N L3 2.2uH RLF7030T-2R2M5R4 56 Q5B Si4816BDY BG3 4 VOUT3 E5 RSNS3 7 10 R25 B Q5A Si4816BDY TG31 10 0.008 5% R57 (Opt) COUT5 22uF 6.3V X5R R59 (Opt) + COUT6 220uF 4V 4TPE220MF VOUT3 3.3V / 5A C49 1uF 6.3V X5R E6 GND 23 R58 R24 C45 (Opt) (Opt) S2N SENS3N 10 TG3 SENS3P SW3 OPT DCR SENSE3 R23 10 SENS1N BG3 INTVCC C46 0.01uF R61 100K A S1N INTVCC 10 R62 100K SENS1P TG3 SW3 BG3 OPTIONAL DCR SENSING R22 TK/SS3 R36 (Opt) TG2 SW2 OPT DCR SENSE2 S2P 0 VOUT2 1.8V / 5A C48 1uF 6.3V X5R E4 23 S3P TK/SS3 BG1 C Q3A Si4816BDY TG2 1 SENS3P R35 SW1 BG1 CIN3 4.7uF 25V 8 26 SENS2P E16 TG1 VIN 30 SENS2N R34 20K 1% SENS1N 31 TK/SS2 TK/SS2 GND 32 18K R33 24.9K 1% VOUT1 2.5V / 5A C47 1uF 6.3V X5R E2 SW1 S3N 1500pF 220uF 4V 4TPE220MF OPT DCR SENSE1 C24 0.1uF 0 C8 C9 R53 (Opt) + COUT2 8 C3 10pF VOUT3 E15 PGOOD3 11 R32 20K 1% 17 EXTVCC 7 R5 63.4K 1% TK/SS1 PGOOD12 BOOST3 SENSE2- E14 23 SGND R31 43.2K 1% TK/SS1 EXTVCC R39 0 ITH3 6 VOUT3 VIN SENSE2+ 15 VFB3 5 1500pF 14 VOUT3 B 33 VINF 12K SENSE1- 220pF DRVCC12 ITH2 4 C7 R46 (Opt) 13 SENSE1+ C43 (Opt) JP3 C6 PGND 3 OFF R4 20K 1% RUN3 2 R51 (Opt) COUT1 22uF 6.3V X5R D1 VIN 1 ON E1 0.008 5% 34 RUN3 35 37 36 RUN1 RUN2 TG1 TK/SS3 SW2 18K 7 SENS1P R7 1500pF VOUT1 R52 R27 BOOST1 U1 LTC3853EUJ S1N RSNS1 (Opt) BOOST2 C4 C5 TK/SS1 41 C TK/SS1 MODE R37 0 RUN2 RUN2 ILIM VIN E12 38 R50 (Opt) 56 23 RUN3 VOUT1 E8 GND L1 1.5uH RLF7030T-1R5N6R1 BG1 4 RUN1 R42 (Opt) C41 (Opt) JP1 ON 1 Q1B Si4816BDY MODE 39 3 OFF R49 0 FREQ RUN1 ON TG1 SW1 RUN1 D + S1P C50 1000pF R63 0 VIN CIN7 22uF 35V CIN1 4.7uF 25V Q1A 8 Si4816BDY 3 D VIN 6.5V - 24V NOTE: When DCR sensing is implemented short RSNS1, RSNS2, RSNS3 and do not populate R21, R22, R23 , R24 , R25 and R26. R21 S1P A 10 EXTVCC C40 0.1uF E10 EXTVCC (5.5Vmax) 5 PGOOD12 E17 PGOOD12 PGOOD3 APPROVALS E18 PGOOD3 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. 4 3 2 DRAWN: Rudy Bautista ENGINEER: Johan Strydom LINEAR TECHNOLOGY CORPORATION 1630 McCARTHY BLVD MILPITAS, CA. 95035 (408)432-1900 (408)434-0507 (FAX) Title: LTC3853EUJ Date: LTC Confidential For Customer Use Only Polyphase 3-Output Step-Down Supply with Tracking APPROVED: CHECKED: www.linear.com SD Document Number Rev Demo Circuit 1254A Tuesday, September 09, 2008 C:\ORCADWIN\CAPTURE\1319A\1254A_REV3.DSN 1 Sheet 3 1 of 2 5 4 3 2 1 D D OPTIONAL MOSFETS VIN Q2A FDS6982AS 56 VIN CIN2 (Opt) 56 Q4A FDS6982AS VIN CIN4 (Opt) Q6A FDS6982AS 56 CIN6 (Opt) C C 4 TG1 TG2 3 SW1 Q2B FDS6982AS 78 3 3 SW3 78 Q4B FDS6982AS Q6B FDS6982AS 2 BG2 4 TG3 SW2 2 BG1 4 2 BG3 1 78 1 1 B B INTVCC VINF R60 0603 (Opt) APPROVALS DRAWN: Rudy Bautista 4.5V < VIN < 5.5V ONLY A ENGINEER: Johan Strydom LINEAR TECHNOLOGY CORPORATION 1630 McCARTHY BLVD MILPITAS, CA. 95035 (408)432-1900 (408)434-0507 (FAX) Title: Date: 5 4 Wednesday, July 09, 2008 3 LTC Confidential For Customer Use Only LTC3853EUJ Polyphase 3-Output Step-Down Supply with Tracking APPROVED: CHECKED: www.linear.com SD Document Number Demo Circuit 1254A Sheet C:\ORCADWIN\CAPTURE\1254A\1254A_00_REV3.DSN 2 Rev 1 3 2 of 2 A