5 4 3 2 1 D D E1 VIN_S J1 63V 63V R17 1M 0603 C1 GND C3 E2 GND_S 28 0.47uF 100V 1206 ENABLE 1 EN 2 14 3 1uF 100V JP1 C 13 1206 R18 (Opt) 0603 12 R3 1M 11 9 R5 (Opt) 4 10 VOUT R7 0 Ohm 5 R9 100k 27 AUXSW1 AUXSW2 VIN INTVCC C2 4.7µF 16V 0603 26 AUXVIN PGND EN BOOST UVLO U1 LT3840EFE#PBF TG OVLO SW PG BG SYNC BGRTN MODE SENSE+ RT SENSE- 2 R2 R11 105k 1% (150kHz) PG E6 SYNC R14 100k C8 100pF R12 13.0k 1% 6 1 2 3 4 CONT PULSE SKIP FB TK/SS 5 6 BURST C11 1nF GND ICOMP ICTRL IMON GND 18 17 16 29 R21 1k JP2 E7 VC C10 2.2nF MODE INTVCC FB 8 Q3 R20 25 C17 (Opt) BSC042NE7NS3 0 Ohm 24 CIN7 2.2uF 100V 1210 CIN8 2.2uF 100V 1210 CIN9 2.2uF 100V 1210 CIN10 (Opt) 1210 CIN11 (Opt) 1210 CIN12 (Opt) 1210 E3 VOUT_S R4 (Opt) 1206 C5 (Opt) 1206 J3 VOUT 0.0025 1% 1W 2512 D2 PDS5100H COUT1 22uF 6.3V 0805 COUT3 (Opt) 0805 COUT2 22uF 6.3V 0805 COUT4 COUT5 COUT6 (Opt) + 680µF + 680µF 6.3V 6.3V 0805 C6 10nF 20 R8 12 7 C7 (Opt) R13 499k 1% J4 VOUT 3.3V / 20A C COUT7 0603 J5 R6 19 15 Q4 BSC042NE7NS3 0 Ohm CIN6 2.2uF 100V 1210 L2 2.2µH HC2LP-2R2-R COOPERBussmann RSNS1 1µF 16V 0603 R19 0 Ohm 22 CIN5 2.2uF 100V 1210 Q2 BSC123N08NS3 C4 23 21 CIN4 2.2uF 100V 1210 D1 1N4448HWS FB E5 B Q1 BSC123N08NS3 INTVCC 1 C16 3 DIS 1µF 16V 0603 AUXBST CIN3 0.22uF 100V 0805 L1 33µH ME3320-333KL 3 CIN2 + 56µF 1 J2 CIN1 + 56µF 2 VIN 4V TO 60V 80V TRANSIENT J6 GND 12 E4 R10 GND_S 825k 1% C9 (Opt) R22 0 Ohm OPTIONAL CIRCUIT C12 2.2nF B TK/SS C13 10nF E8 U2 LT3009ESC8-5#PBF INTVCC GND 5 E9 GND C14 1uF 16V 0805 ICTRL E10 ICTRL 1 IN OUT SHDN ADJ 5V 6 C15 1uF 10V 0603 7 GND GND GND 2 3 R15 3.74M 1% 0603 ICTRL 4 E11 R16 TBD 0603 IMON E12 GND E13 GND A A CUSTOMER NOTICE NOTE: UNLESS OTHERWISE SPECIFIED. 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. 1. ALL RESISTORS 0402. 2. ALL CAPACITORS 0402. C:\PADS PROJECTS\1909A(LT3840EFE)\SCH\1909A_REV2.DSN THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 2 TECHNOLOGY LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY TITLE: SCHEMATIC WIDE INPUT RANGE, HIGH EFFICIENCY, SYNCHRONOUS BUCK CONVERTER WITH ACCURATE CURRENT LIMIT SIZE N/A SCALE = NONE 1630 McCarthy Blvd. Milpitas, CA 95035 www.linear.com Phone: (408)432-1900 Fax: (408)434-0507 IC NO. REV. LT3840EFE DEMO CIRCUIT 1909A MODIFY DATE: Jun 19, 2014 2 SHEET 1 1 OF 1