5 4 3 2 1 VOUT1 TRK/SS1 0 R4 20.0K R12 (OPT) R7 2.49K C6 10nF CIN1 4.7uF 25V 10K C2 1000pF VOUT1 * C9 2.2nF R25 8.2K C11 2.2nF C12 C18 22pF 1 5 ITH1 VIN 22 INTVCC 21 VFB1 8 VFB2 9 ITH2 1 SENSE2- BOOST2 18 C15 12 SENSE2+ TG2 17 SW2 16 S2+ RUN2 A RSENSE B DCR SENSE RSNS1 0.008 Ohm (OPT) 10 Ohm (OPT) 1 8 7 C R21 2.2 TG2 BG2 Q2A 4 VSW2 1 * J2 VOUT2 * SUMIDA CDEP85-2R4MC-50 RSNS2 COUT4 22uF 6.3V 2 2 COUT3 220uF 4V VOUT2 2.5V@5A E8 C17 1uF 6.3V COUT6 (OPT) GND E10 FDS6982AS D3 C19 0.1uF L2R23* L2 2.4uH C14 0.1uF Q2B R36 0 S2+ VSW2 R38 R37 (OPT) 0 INTVCC LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY INTVCC VIN CIN5 (OPT) VINF Customer Notice CIN6 (OPT) 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 Technology Applications Engineering For Assistance. This Circuit Is Proprietary To Linear Technology And Supplied For Use With Linear Technology Parts. R41 C7 J1 R6 R13 R17 10 Ohm 1nF (OPT) (OPT) (OPT) (OPT) (OPT) 0.1uF SHORT 3.01K 20.0k 0 Ohm RSNS2 0.008 Ohm (OPT) R29 10 Ohm (OPT) R26 TG1 Stuff R41 with 0 Ohms for 4.5V < Vin < 5.5V C15 J2 R23 R22 10 Ohm 1nF (OPT) (OPT) (OPT) (OPT) 0.1uF SHORT 3.01K 0 Ohm TG2 VSW1 1 7 6 5 BG1 R27 Q3 Si4816BDY (OPT) 4 (OPT) VSW2 1 7 6 5 BG2 Q4 Si4816BDY 4 (OPT) 4 LINEAR TECHNOLOGY CORPORATION 1630 McCARTHY BLVD. MILPITAS, CA. 95035 408-432-1900 408-434-0507 FAX Title 20.0k OPTIONAL MOSFETS & CIN 5 GND CIN2 4.7uF 25V VINF C13 4.7uF VOUT1 3.3V@5A 1 VIN D1 OFF R14 COUT5 (OPT) JP2 RUN2 PHASE2 R11 0 2 DESC E4 C5 1uF 6.3V R33 100K PHASE1 U1 COUT2 22uF 6.3V COUT1 220uF 4V B (OPT) A R16 3 C20 (OPT) * J1 VOUT1 PGOOD 3 R34 (OPT) RSNS1 SUMIDA CDEP85-2R4MC-50 ON 2 E11 * L1 2.4uH E6 INTVCC 2 INTVCC SGND GND E3 L1- 8 RUN2 PGND 19 Q1B * 2 3 RUN2 20 11 ILIM R32 (OPT) BG2 TK/SS2 * C4 0.1uF INTVCC 10 R40 VOUT2 0 VIN 27 28 FREQ 23 7 R30 43.2K 24 BG1 R29 OFF BOOST1 TK/SS1 3 C16 (OPT) * R27 25 LTC3850EGN BG1 8 R39 (OPT) * ON 2 E9 JP1 RUN1 TG1 SENSE1+ 4 TRK/SS2 * RUN1 B * R22 R26 R24 (OPT) RUN1 L2- 330pF 26 SENSE1- 6 E12 SW1 3 TRK/SS1 R20 20.0k VIN R6 3 R17 C7 R19 20.0k ILIM ILIM 220pF R15 10K VSW1 5 6 E13 C VSW1 D 1 C8 * L1- 2 * * R13 PGOOD R9 63.4K R14 PGOOD CIN4 22uF 35V 15 4 C3 22pF * MODE R11 RUN1 S1+ FCC PGOOD 1 BURST 3 C10 (OPT) U1 ILM 2 E7 R35 0 PULSE SKIP 14 R18 0 MODE JP3 SYNC RUN1 RUN2 SYNC SYNC Q1A VIN 6.5V - 24V E1 S1+ 4 R3 0 13 1 INTVCC VIN FDS6982AS TG1 2 C1 (OPT) D E5 VIN INTVCC R2 8 3 7 E2 FSW = 400KHz, Type R10 TRK/SS1 5 6 R1 43.2K TRK/SS2 TRK/SS2 3 2 Dual Output, Dual Phase 5A Synchronous Buck Converter Size Document Number Date: Thursday, December 13, 2007 Demo Circuit 1231A-A/B LTC3850EGN Sheet 1 1 of 1 Rev A