5 4 3 2 1 VIN1 D D E2 E1 VIN1 6V TO 40V TRANSIENT TO 60V E3 GND PG1 E5 150k 18 PG C17 E7 SYNC MODE SYNC 1 10pF (OPT) 10k (OPT) 2 16 R10 1 BD BOOST 5 9 IN2 1 2 200k 1% 100k 1% 47nF C6 0.1µF 16V GND E16 IN2 15 11 0 Ohm IN2 PG2 IN3 C10 1µF 16V R15 B R17 158k 1% VOUT2 R13 E15 FB1 C15 1206 (OPT) MMZ1608S601AT 0603 (OPT) E11 340k 1% GND R18 0 Ohm E17 IN3 B 499k 1% E12 PG3 + C1 10uF 63V 1. ALL RESISTORS 0603. 2. ALL CAPACITORS 0603. SEE DEMO MANUAL FOR CURRENT CAPABILITY. * E13 VOUT3 3.3V / 200mA C11 4.7µF 10V 0805 C12 TBD E14 GND CUSTOMER NOTICE 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. APPROVALS TECHNOLOGY PCB DES. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 4 3 1630 McCarthy Blvd. Milpitas, CA 95035 www.linear.com Phone: (408)432-1900 Fax: (408)434-0507 A LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY TITLE: SCHEMATIC APP ENG. 40V STEP-DOWN REGULATOR WITH DUAL LDOS SIZE C:\PADS PROJECTS\1869A(LT3776EUDD)\SCH\1869A_REV3.DSN 5 R16 150k VIN1 NOTE: UNLESS OTHERWISE SPECIFIED. A E10 C8 TBD VOUT3 VIN1_EMI 4.7uH C16 CDRH2D18/LDNP-4R7NC Sumida 1206 (OPT) (OPT) R11 150k VOUT2 2.5V / 200mA C7 4.7µF 10V 0805 EMI Filter L2 C E9 14 13 * E6 931k 1% R6 R14 158k 1% IN3 R20 C14 FB2 PG3 VOUT1 R19 21 22 NC NC 1.50k 1% 22pF R7 10 5V / C5 22µF 10V 0805 6 JP4 EN3/ILIM3 12 3 EN 47nF R12 OUT2 OUT3 C13 17 7 DIS C4 C9 1µF 16V FB3 EN3 1.50k 1% D1 DFLS160-7 EN2/ILIM2 GND 3 JP3 SYNC E4 VOUT1 R9 294k 1% PG2 JP2 2 EN 2 23 U1 LT3667EUDD#PBF RT 3 RT 1 174k 1% fs=600kHz 4 25 EN2 R8 FB1 8 C R21 DA PG VOUT1 CDRH4D22HPNP-220MC R5 JP1 DIS SW L1 22uH 24 VOUT1 3 DIS EN PG1 3 UVLO1 2 0.22µF 20 19 (OPT) 1 R3 150k 0 Ohm C3 IN1 GND ENABLE EN R2 R4 E8 VIN1 C2 2.2µF 100V 1206 R1 1M IC NO. N/A SCALE = NONE 2 MODIFY DATE: REV. LT3667EUDD DEMO CIRCUIT 1869A Aug 19, 2014 13:18:19 3 SHEET 1 1 OF 1