5 4 3 2 1 REVISION HISTORY ECO REV __ 2 DESCRIPTION APPROVED DATE PRODUCTION CHARLIE Z. 4-23-12 D D TP3 R20 0 INTVCC R7 100K TP4 100 R16 1K TP10 JP2 MODE PULSE SKIP CCM 1 2 CC1 CC2 RC 0.01uF 13K 3 C11 68pF 1 100pF 2 3 4 R21 5 121K R24 10K 6 VIN+ JP1 RUN ON INTVCC 1 2 OFF 3 R30 41.2K R31 12.1K B D8 BZX84C5V1 R22 OPT C7 0.1uF 50V 7 C8 0.1uF 8 50V R25 0 R14 100 9 R13 100 17 SENSE1- BOOST1 ITH PGND SGND BG1 R11 22 C4 0.22uF 16V GND INTVCC RUN BG2 VINSNS BOOST2 VOUTSNS TG2 ILIM SW2 TRIM C18 10uF 18 6.3V D7 DFLS160 VOUT R26 10 0805 C24 1uF 16V 5 6 3 VOUT C19 C20 22uF 16V 1210 0.25W TP13 + COUT1 OPT 16V 12V / 2.5A MAX R8 10 VOS+ C D6 DFLS160 TP14 GND Q2B Si4288DY C13 (OPT) 2 R29 (OPT) R1 0 16 15 C22 0.22uF 16V 14 13 12 B R18 0.015 1W R6 OPT C10 TP12 C12 (OPT) 1206 D5 DFLS160 0 INTVCC FREQ 4 C29 C23 (OPT) 1210 XAL7070 4 R27 C17 C16 22uF 16V 1210 L1 5.6uH Q1A Si4288DY 20 MODE/PLLIN EXTVCC 0 D4 DFLS160 21 7 8 1 19 VIN R17 0 SENSE1+ 10 VOUT VIN+ SW1 R23 0 24 R28 (OPT) 1206 Q2A Si4288DY 7 8 R10 28 SS 23 Q1B Si4288DY 2 1 100 TG1 R2 0.015 5 6 R9 INTVCC EXTVCC TP7 VOUT VOUT1 3 TP5 VFB SGND 27 IOSENSE- 26 10 29 CF1 OPT CSS 0.1uF 25 U1 LTC3789EUFD 11 CF 22pF PGOOD RFB1 113K C15 1uF 50V 0805 IOSENSE+ RFB2 8.06K PLLIN C14 (OPT) 1210 VIN 6V - 36V R5 VOS+ SS C35 (OPT) 1210 C26 10uF 50V 1210 VIN+ PGOOD C TP6 C9 C25 10uF 50V 1210 VIN+ R12 OPT 2.2uF R4 100 R3 100 NOTE: UNLESS OTHERWISE SPECIFIED A A CUSTOMER NOTICE 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. 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 HZ CHARLIE Z. TITLE: SCHEMATIC HIGH EFFICIENCY COMPACT BUCK-BOOST CONVERTER SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only N/A SCALE = NONE DATE: IC NO. REV. LTC3789EUFD DEMO CIRCUIT 1881A Tuesday, May 15, 2012 2 SHEET 1 1 OF 1