A B C D E NOTE: VOUT1 R1 10K S128 SENSE1- 1 TRK/SS1 2 ITH1 3 VFB1 4 VFB2 JP1 RUN1 1 E10 R36 OPT C18 OPT 2 ON 3 OFF RUN2 C21 OPT 3 VIN 19 INTVCC 18 S2+ R19 43.2K 8 29 VOUT2 RUN2 ON GND D1 CMDSH-3 VINF INTVCC R12 2.2 16 BOOST2 15 VL21 7 6 5 C9 4.7uF 10V SENSE2PGND SI4816BDY TG2 17 C10 0.1uF 3 CIN2 4.7uF 16V Q2 BG2 VSW2 2.2uH TDK RLF7030 4 VOUT2 RSNS2 0.008 L2 VOUT2 1206 OFF TG2 14 SW2 13 R18 0 Ohm GND E6 VSW2 CIN4 OPT R24 100K PGOOD EXTVCC E12 EXTVCC R26 OPT PGOOD VSW1 3 7 8 BG1 NOTE: When DCR sencing is implemented short RSENSE1 and RSENSE2. 1 Do not stuff R7,R9,R20 or R21 R29 OPT Stuff R41 with 0 Ohms for 4.5V VIN 5.5V R40 OPT V R32 OPT R41 OPT VL2- V R34 OPT 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 TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. A 2 OPTIONAL MOSFETS Q4 FDS6982AS OPT R39 OPT S2- S2+ VSW2 1 VINF INTVCC R27 OPT 3 7 8 BG2 Q3 FDS6982AS OPT VL1- S1- S1+ VSW2 4 2 VSW1 TG2 4 R25 0 Ohm E14 OPTIONAL DCR SENSING 2 CIN5 OPT VIN TG1 PGOOD 2.5V / 5A C23 1uF 6.3V D2 CMDSH-3 C14 0.1uF EXTVCC E5 COUT4 220uF + 4V COUT3 10uF 6.3V SENSE2+ SGND C22 1uF 6.3V + E4 5 6 R38 OPT 2 20 C16 1000pF 1 E11 BG1 BG2 7 R21 10 JP2 RUN2 RUN2 21 TRK/SS2 9 2 C13 100pF C15 22pF VIN R37 OPT S2- R20 10 BOOST1 PGOOD RUN1 Q1 SI4816BDY 12 RUN1 6 22 ITH2 TRK/SS2 C12 1000pF R17 7.5K EXTVCC R35 OPT 5 R16 20.0K VIN TG1 LTC3850EUF E3 COUT2 220uF 4V 5 6 R14 20.0K C17 OPT 11 R23 0 Ohm 23 R10 0 Ohm 1206 COUT1 10uF 6.3V SW1 U1 ILIM E9 3 RUN2 SYNC C8 1000pF 10 R11 10K 4 VOUT1 3.3V / 5A 1 R9 10 4 E2 VOUT1 RSNS1 0.008 L1 2.2uH TDK RLF7030 BG1 C5 0.1uF TRK/SS1 SYNC 5 R31 0 Ohm VSW1 7 6 2 C7 100pF SENSE1+ VL11 8 R15 OPT 27 CIN3 39uF 16V + GND TG1 VSW1 RUN1 C4 1000pF C11 10nF R4 3.32K S1+ R7 10 R8 63.4K R30 OPT 2 E8 C6 15pF SYNC 25 TRK/SS1 R13 0 Ohm TRK/SS1 C2 1000pF CIN1 4.7uF 16V 3 R5 20.0K FREQ C3 OPT 26 4 R22 0 Ohm 8 E7 VIN 6.5V to 14V E1 3 Fsw=500kHz,typ INTVCC 24 R3 43.2K RUN1 TRK/SS2 TRK/SS2 VIN MODE Converter is setup for coincident rail tracking B C CONTRACT NO. APPROVALS DATE DRAWN Antonina Karpova 6/19/06 CHECKED APPROVED ENGINEER Mike Shriver 6/19/06 DESIGNER Friday, June 15, 2007 D TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 1 TITLE LTC3850EUF 3.3V/5A and 2.5V/5A REGULATOR SIZE CAGE CODE SCALE: FILENAME: DWG NO REV DC1126A SHEET E 1 3 OF 1