5 4 3 2 1 REVISION HISTORY ECO __ PGOOD2 E1 RUN2 DESCRIPTION 2 PRODUCTION APPROVED DATE 12-19-12 RUN2 E2 EXTREF2- S1+ VOS1+ R29 2.2 INTVCC 26 C9 25 1uF C16 C8 4.7uF 16V 0805 8 2 7 R23 0 J2 E7 VIN 4.5V - 14V GND VIN- VOUT2 COUT6 100uF 6.3V 1206 2512 VIN+ COUT7 + COUT8 + COUT9 COUT10 + 330uF 330uF OPT 100uF 2.5V 2.5V 6.3V 7343-D15T 7343-D15T 7343-D15T 1206 C22 10uF 6.3V 0805 J3 J4 VOUT2 1.2V / 20A GND C VIN R31 2.2 CIN1 22uF 16V 1210 1 2 SW1 TG1 J1 1 R28 OPT S2- 23 22 CIN6 + 180uF 16V 16SVP180MX DCR SENSE FILTER / DIVIDER FOR PHASE 2 C10 0.1uF 24 6 5 EXTVCC 27 R25 0 RS2 0.001 0.47uH CIN2 22uF 16V 1210 21 S1+ R33 20 C14 0.1uF OPT 9 D1 CMDSH-4 R34 OPT L1 0.47uH 0 COUT1 100uF 6.3V 1206 2512 S1- BG1 S1- COUT2 100uF 6.3V 1206 + COUT3 OPT 7343-D15T + COUT4 + COUT5 330uF 330uF 2.5V 2.5V 7343-D15T 7343-D15T C21 10uF 6.3V 0805 J5 J6 DCR SENSE FILTER / DIVIDER FOR PHASE 1 19 Q1 BSC0911ND VOUT1 RS1 0.001 R37 OPT 8 R35 PGOOD1 0.01uF BG2 28 + CIN5 OPT CAP-SVP-F8 R26 OPT 29 Q2 BSC0911ND CIN8 OPT 1210 S2+ L2 9 7 TG1 3 4 VOUTSENSE1+ SW2 30 3 33 34 32 BOOST2 PGOOD2 35 DTR2 RUN2 36 37 SW1 R43 OPT 0 SENSE2- 38 BG1 TRACK/SS1 13 E12 DRVCC1 ITH1 C13 R36 OPT R38 TRK/SS1 VIN 18 12 VOUT2 PGND VOUTSENSE1- 4 11 C12 470pF INTVCC 31 CIN7 OPT 1210 CIN4 22uF 16V 1210 R22 OPT PHASE 15K EXTVCC PHASMD 10 47pF DRVCC2 MODE/PLLIN RUN1 1 R32 3 TRACK/SS2 RT 9 C11 BG2 SGND 8 FSW = 300kHz ITH2 CLKOUT 7 R30 133K SW2 D2 CMDSH-4 4 6 TG2 VRNG/(EXTVREF2) * DTR1 E11 E4 CIN3 22uF 16V 1210 6 4 VDFB2+ 17 * 5 2 C4 0.1uF VO2_SNS- E6 VIN R21 0 16 4 3 E9 JP3 INTVCC PHASMD RUN2 OPT 5 2 * OPT RUN1 R15 VO2_SNS+ E3 DTR2 PHASE 1 C6 * C7 120 DEG 90 DEG 60 DEG INTVCC DTR1 R9 TG2 * SENSE1- R20 OPT C5 47pF R27 CLKOUT R13 R62 SENSE1+ * VDFB2- INTVCC EXTREF2+ 3 C * SENSE2+ * 2 PLLIN C3 S21nF S2+ 15 1 U1 SEE TABLE R24 FCM SYNC DCM R8 100K OPT R16 OPT R19 10K R12 DTR2 C2 R5 0 DTR2 INTVCC JP2 MODE R11 10K 14 R18 OPT 0 INTVCC OPT VOS1+ OPT VDFB2+ * INTVCC OPTIONAL COMPONENTS FOR SINGLE OUTPUT, DUAL PHASE OPERATION R7 10 R10 R14 39 R17 E5 D R6 10 R4 * C1 OPT R3 OPT TRK/SS2 10K * PGND 1 2 R2 R61 R1 OPT BOOST1 VIN JP1 RUN2 ON OFF 3 D REV R41 0 R45 VOUT1 1.5V / 20A GND R42 0 INTVCC ON OFF R47 OPT 2 R49 OPT 3 B C15 OPT VIN 1 JP4 RUN1 C17 OPT RUN1 R48 10 R50 0 GND VO1_SNS+ E13 OPT R46 10 VO1_SNS- E14 B R39 OPT DTR1 E15 E16 NOTE: TIE SGND PIN TO PGND PAD UNDERNEATH IC. EXTVCC EXTVCC 100K 1nF R63 R44 10K INTVCC RUN1 PGOOD1 R40 15K E17 C18 1uF E18 A NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. 2. INSTALL SHUNTS ON JUMPERS AS SHOWN. * A ASSEMBLY U1 DC1997A--A LTC3838EUHF-1 DC1997A--B U2 LTC3838EUHF-2 OPT R24 0 C19 C23 R14 R61 E19 E20 JP5 JP6 R51 0 OPT OPT OPT OPT OPT OPT OPT OPT OPT OPT OPT OPT 10k LT6650HS5 100k OPT 0 R62 0 C20 1uF 4.7uF STUFF STUFF 10k R53 R54 20k 10k 0.1% 0.1% R59 0 R60 6.65k 0.1% R52 R4 R12 R27 C6 10k 11k 330pF 0.01uF 20k OPT OPT 5.23k POT * PIN 2 = VRNG FOR LTC3838-1, EXTVREF2 FOR LTC3838-2 680pF C7 C24 D3 OPT OPT 4.7nF 0.01uF BZT52C5V6S CUSTOMER NOTICE APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. TECHNOLOGY LT M. SHRIVER TITLE: SCHEMATIC FAST TRANSIENT DUAL OUTPUT STEP-DOWN DC-DC CONVERTER SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 2 IC NO. N/A SCALE = NONE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: REV. LTC3838EUHF-1/-2 2 DEMO CIRCUIT 1997A DEC 19, 2012 SHEET 1 1 OF 2 5 4 3 2 1 D D OPTIONAL MOSFETS EXTERNAL REFERENCE FOR DC1997A-B ASSY, OPTIONAL ON DC1997A-A ASSY VIN VIN FB Q10 OPT * 0.01uF 1 * GND 2 NOTE: FOR ACCURATE EFFICIENCY MEASUREMENTS AT LIGHT LOAD IN DCM, REMOVE R51, PUT JP6 IN EXT POSITION AND CONNECT REFERENCE VOLTAGE BETWEEN E19 AND E20. Q4 OPT 4 CIN9 OPT 1210 ON BD REF FIXED 1.2V ADJ 0.8V to 1.5V * * * EXTREF2C LOAD STEP 5mV / A 5% DUTY CYCLE MAX ISTEP1+ ISTEP1- E25 E27 5 4 3 2 Q11 FDD8874 1 E21 R55 10K 3 Q6 OPT R57 0.005 2010 VOUT1 J8 2 2 5 4 3 2 5 4 E20 R59 0 PULSE1 LOAD STEP 5mV / A 5% DUTY CYCLE MAX GND E23 OPTIONAL COUT 1 VOUT2 1 2 3 Q5 OPT VOUT2 1.2V 0.8V to 1.5V EXTREF2- VOUT2 1 J7 5 C23 1uF LOAD STEP CIRCUIT #2 VOUT1 VOUT1 1 2 3 6.65k 0.1% 0603 R52 * 20k 2 BOURNS 3313J-1-203E ROTATIONAL LIFE = 100 CYCLES TURN CW TO INCREASE VEXTREF LOAD STEP CIRCUIT #1 SW1 4 EXTREF2+ CIN10 OPT 1210 1 2 3 1 2 3 4 BG1 R60 * ISTEP2+ ISTEP2- E26 E28 Q12 FDD8874 + COUT11 + COUT12 OPT OPT 7343-D15T 7343-D15T 1 R56 10K 3 Q3 OPT 5 5 C TG1 * E19 1 2 3 4 1 2 3 C19 1uF VOUT C24 * * EXT 1 C20 * 4.7uF 16V 0805 5 1 REF 3 5 5 Q9 OPT 4 4 R53 * 20k ON BD REF 0603 0.1% ADJ 2 FIXED JP5 R54 * 10k 0603 0.1% JP6 3 1 D3 * BZT52C5V6S BG2 * 3 1 2 3 10k 1% SW2 ON BD U2 LT6650HS5 R51 * 2 VIN CIN11 CIN12 OPT OPT 1210 1210 1 4 1 2 3 4 Q8 OPT 2 Q7 OPT 5 5 EXTREF2+ TG2 R58 0.005 2010 E22 E24 PULSE2 VOUT2 GND + COUT13 + COUT14 OPT OPT 7343-D15T 7343-D15T B B A A CUSTOMER NOTICE APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. TECHNOLOGY LT M. SHRIVER TITLE: SCHEMATIC FAST TRANSIENT DUAL OUTPUT STEP-DOWN DC-DC CONVERTER SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 2 IC NO. N/A SCALE = NONE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only LTC3838EUHF-1/-2 DEMO CIRCUIT1997A DATE: DEC 19, 2012 SHEET 2 1 REV. 2 OF 2