REVISION HISTORY ECO REV DESCRIPTION 0 1 2 DATE APPROVED 1st PROTOTYPE 04-10-08 George Yu. PRODUCTION 01/05/09 Chuen MT 01-27-10 Fran H. Value Change: R4 from 1.50M to 1M 1%, R5 from 332k to 221k 1% Value Change: L2 & L3. E1 VIN 2.4V - 5V VIN + E2 CIN1 47uF 10V GND ON CIN2 4.7uF 10V SHDN1 1 CIN3 4.7uF 10V CIN4 4.7uF 10V U1 LTC3521EUF 3 1 9 R1 VOUT1 R2 VOUT2 4 PGOOD1 3 2 PGOOD3 15 E10 PGOOD2 E11 PGOOD3 11 22 R6 137K 1% C1 22pF GND C5 10uF 6.3V 0805 C4 22pF R8 102K 1% VOUT3 1.2V / 600mA C7 0.1uF E8 23 GND PGND2 PGND1B R9 100K 1% 18 FB1 FB3 E7 VOUT3 CDRH2D18/HP-3R3NC Sumida VOUT1 12 C10 (Opt) 17 SW1B C9 (Opt) 8 L3 3.3uH SW1A GND R4 1.00M 1% E6 24 PGOOD3 6 C3 22uF 6.3V 1206 C6 0.1uF R7 68.1K 1% PGND1A 16 R5 221K 1% E9 VOUT2 1.8V / 600mA PGOOD2 21 14 E4 PGOOD1 E5 VOUT2 C2 10uF 6.3V 0805 PGOOD1 SW3 VOUT1 GND SHDN3 GND R3 1M 4.7uH CDRH5D16NP-4R7NC Sumida C8 0.1uF L2 3.3uH 20 CDRH2D18/HP-3R3NC Sumida FB2 PGOOD2 7 1M VOUT3 L1 E3 SHDN2 25 3 JP4 VOUT1 3.3V / 1A PWM 1M 2 OFF SHDN1 SW2 JP3 ON PVIN2 10 2 PVIN1 5 VIN SHDN2 1 SHDN3 1 BURST JP1 3 OFF PWM 3 JP2 ON MODE 2 2 OFF 1 PGOOD1 PGOOD2 PGOOD3 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 RB Fran H. SYNCHRONOUS 1A BUCK-BOOST AND DUAL 600mA BUCK CONVERTER N/A SCALE = NONE TITLE: SCHEMATIC SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 1630 McCarthy Blvd. Milpitas, CA 95035 www.linear.com Phone: (408)432-1900 Fax: (408)434-0507 DATE: IC NO. REV. LTC3521EUF DEMO CIRCUIT 1389A Thursday, February 11, 2010 2 SHEET 1 OF 1