6 5 4 3 2 1 4 4 C44 4.7µF 100V 1812 M2 R58 2 TG1 PGND C48 4.7µF 100V 1812 C49 4.7µF 100V 1812 C68 OPT. C69 OPT. 4 4 4 M2-1 R59 OPT. BG2 BG1 TG1 R41 2 R40 0.010 1225 Wide TP13 AGND TG2 R51 2 R60 OPT. TP4 PGND 3 1 SRVO_FBOUT D6 2 1 D5 2 SRVO_IOUT 1 R42 549 R43 549 R45 549 R44 549 R16 10K 31 30 TP15 SRVO_FBIN TP16 SRVO_IIN 6 25 26 27 28 36 10 TP17 SRVO_IOUT TP18 SRVO_FBOUT PGND VC SRVO_IIN 2 2 TG2 BOOST2 SW2 BG2 CSN CSP BG1 SW1 R27 100K R13 392K 20 24 D4 1 D3 18 19 17 16 2 3 14 21 23 BOOST1 TG1 GATEVCC GATEVCC IMONOUT 15 INTVCC IMONIN 35 R54 OPT. FBOUT SRVO_FBIN SRVO_IIN SRVO_IOUT SRVO_FBOUT SWEN CLKOUT FBIN RT 0 CSNOUT AGND R55 5 N/C N/C CSPOUT #SHDN SYNC LDO33 FBIN C14 1nF VIN SS 1 LDO33 34 CSPIN MODE R11 71.5K CSNIN EXTVCC 33 22 U1 LT8705EUHF 32 LDO33 OPT. C15 1nF SRVO_FBIN 2 2 1 D2 C13 0.22µF CMMR1U-02 R9 10 1 D1 R8 10 C47 0.22µF C12 R53 OPT. + C64 220µF 100V M4-1 OPT. 4 M3-1 OPT 4 R39 0 CMMR1U-02 4.02 R14 20K + C55 220µF 100V C51 4.7µF 100V 1812 R62 GATEVCC 3 C46 1.0µF 100V 0805 C50 4.7µF 100V 1812 8 7 6 5 1 2 3 4 OPT. R38 2 TP5 /SHDN C71 OPT. C70 OPT. TG2 1 2 3 M1-1 OPT TP12 AGND TP2 VOUT 48V / 5A VOUT 0.007 2512 R22 0 M3 BSC039N06NS BSC123N08NS3 G 8 7 6 5 TP3 R57 7 6 5 8 7 6 5 C43 4.7µF 100V 1812 1 2 3 C54 OPT. C53 OPT. C67 OPT. 1 2 3 C66 OPT. 5 6 7 8 8 7 6 5 C42 4.7µF 100V 1812 3 2 1 C41 4.7µF 100V 1812 1 2 3 22µH 5 6 7 8 + C45 220µF 100V L1 1 2 3 4 + C52 220µF 100V 8 7 6 5 0 2512 M4 BSC039N06NS 8 4 R56 VIN 36V to 80V 3 2 1 TP1 M1 BSC123N08NS3 G TP19 SWEN TP10 MODE JP1 1 FCM 2 BURST SEE NOTE 3 VOUT 3 DCM 4 8 39 7 2 TP14 CLKOUT EXTVCC C65 1.0µF 100V 0805 C61 R49 24.3K 0.1uF R47 210K C59 1µF C58 4.7µF R50 56.2K R46 100K TP20 EXTVCC LDO33 TP8 LDO33 38 12 13 11 9 4 C56 4.7µF 37 C57 4.7µF 29 2 R48 0 C60 OPT. C62 220pF 25V C63 3300pF 25V TP9 SS TP11 SYNC 1 CUSTOMER NOTICE NOTES (UNLESS OTHERWISE SPECIFIED): ____________________________ 1- ALL SMD CAPACITORS ARE 16V. 2- ALL SMD CAPACITORS AND RESISTORS ARE 0603. 3- CUT TRACE TO DISCONNECT EXTVCC FROM VOUT AND SUPPLY EXTVCC THROUGH TP20. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 6 5 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. S. M. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. MEHDI A. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 4 3 TECHNOLOGY TITLE: SCHEMATIC 80V / 48V Synchronous Buck-Boost Controller SIZE N/A SCALE = NONE 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: IC NO. LT8705EUHF REV. 2 DEMO CIRCUIT 1924A Wednesday, July 02, 2014 SHEET 1 1 OF 2 1 A B C D E 4 4 BOARD STANDOFF HARDWARE MH1 3 MH2 3 NYLON STACKING SPACER #4 0.5" NYLON STACKING SPACER #4 0.5" MH3 MH4 NYLON STACKING SPACER #4 0.5" NYLON STACKING SPACER #4 0.5" 2 2 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. S. M. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. MEHDI A. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 1 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. A B TECHNOLOGY TITLE: SCHEMATIC 80V / 48V Synchronous Buck-Boost Controller SIZE N/A SCALE = NONE C 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: IC NO. REV. LT8705EUHF 2 DEMO CIRCUIT 1924A Friday, July 11, 2014 D SHEET 2 E OF 2 1