A B C D E REVISION HISTORY ECO REV __ RTR1 RTR3 OPT SVIN RSS1 VIN 3 4 5 6 TRACK EXT SS INT 4.7M U1 LTC3618EUF PGOOD1 VIN 2.25V - 5.5V 100k E5 E6 CIN6 100uF GND 18 VIN + CIN5 100uF OPT CIN4 22uF 6.3V 1206 + CIN3 22uF 6.3V 1206 CIN2 22uF 6.3V 1206 21 22 CIN1 22uF 6.3V 1206 23 RFILT 24 CFILT 1uF E7 9 10 3 E9 VIN 3 PGOOD2 16 7 100k 15 PGOOD1 ITH1 VDDQ EXT REF E11 05-24-11 PVIN1 FB1 VDDQ EXT REF 1 2 3 4 SVIN 5 6 4 CITH1 470pF 0805 2 C1 10pF FB2 PVIN2 SW2 PGOOD2 VDDQIN RT SW2 ITH2 COUT5 100uF OPT 1 4 E3 845k 1% GND GND E4 JP2 1.8V 422k 1% R7 VOUT1 SELECT JP3 2.5V JP4 OPT OPT PVIN2 + VDDQ +/- 3A R1 1.5V 562k 1% R5 267k 1% R9 SVIN RUN2 JP1 R3 19 5 L2 3 11 1.0uH COILCRAFT XFL4020-102ME 12 6 10pF E8 EXT INT 3 1 COUT4 10uF 6.3V 0805 COUT2 47uF 6.3V 1210 JP10 COMP2 C2 RT 402K JP13 VDDQIN 3 E2 COUT7 100uF 6.3V OPT 1210 CFFW1 10pF 2 20 PVIN1 4 2 SW1 RUN1 1 RITH1 15.8k 1% 0805 1 JP12 ON RUN2 OFF 13 RPG2 TRACK/SS1 PGND 14 SGND RPG1 25 VIN SW1 VTTR ON 24 1 RUN1 2 EXT 8 3 0.01uF OFF DATE FRAN H. COUT3 10uF 6.3V 0805 COUT1 47uF 6.3V 1210 SVIN JP9 COMP1 INT SS 17 CSS1 JP11 APPROVED PRODUCTION VDDQ 1.0uH COILCRAFT XFL4020-102ME PHASE 4 DESCRIPTION L1 JP5 TRACK / SS1 1 2 100k MODE/SYNC E1 3 TRACK1 2 COUT8 100uF 6.3V OPT 1210 + COUT6 100uF OPT E10 4 RITH2 10k 1% 0805 2 SVIN VTT +/- 3A E12 CITH2 680pF 0805 GND GND VTTR +/-10mA C4 0.1uF E13 C3 0.1uF 2 2 JP6 PHASE 180 deg 90 deg IN PHASE 1 2 3 4 5 6 JP8 MODE EXT SYNC 1 1 2 PSM 3 4 FCM (FORCED CONTINUOUS) 5 6 EXT (EXTERNAL SYNC) (PULSE-SKIP) E14 CUSTOMER NOTICE NOTE: UNLESS OTHERWISE SPECIFIED 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. 1. ALL RESISTORS ARE IN 0603. ALL CAPACITORS ARE IN 0603. APPROVALS PCB DES. TECHNOLOGY JW APP ENG. FRAN H. TITLE: SCHEMATIC SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. A B C N/A SCALE = NONE D DATE: IC NO. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DUAL 3A MONOLITHIC SYNCHRONOUS STEP-DOWN REGULATOR FOR DDR MEMORY REV. LTC3618EUF DEMO CIRCUIT 1726A Friday, July 29, 2011 2 SHEET 1 E OF 1 1