QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 441 1.25A SYNCHRONOUS BUCK REGULATOR LTC3411 DESCRIPTION Demonstration circuit 441 is a constant-frequency stepdown converter, using the LTC3411 monolithic synchronous buck regulator. The DC441 has an input voltage range of 2.65V to 5.5V, and is capable of delivering up to 1.25A of output current. In Burst Mode operation, the DC supply current is typically only 240µA at no load, and less than 1µA in shutdown. In switching-noise sensitive applications, pulling the MODE pin to SGND inhibits Burst Mode operation. These features, plus the LTC3411 coming in a small 10-Pin MS package and having an operating frequency of 1MHz (allowing the exclusive use of low profile surface mount components), make the DC441 demo board an ideal circuit for use in battery-powered, hand-held applications. Design files for this circuit board are available. Call the LTC factory. QUICK START PROCEDURE Demonstration circuit 441 is easy to set up to evaluate the performance of the LTC3411. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: NOTE: When measuring the output ripple, see Figure 2 for proper scope probe technique. 1. Select the desired output voltage using jumper JP2. The fixed output voltages are 1.8V, 2.5V, and 3.3V (as shown). There is also an option to set the output voltage to a custom value by inserting a resistor into the RFB5 pads next to jumper JP2. 2. Connect the input power supply to the Vin and GND plug Vin or increase Vin over the rated maximum supply voltage of 5.5V, or the part may be damaged. 3. Connect the load between the Vout and GND termi- nals on the right-side of the board. 4. Select the desired operating mode using JP1. To se- lect pulse-skipping mode, tie to ground by inserting the jumper into the rightmost position. Inserting the jumper into the leftmost position connects the pin to Vin, which allows Burst Mode operation. 5. To shut down the circuit, connect the SHDN/RT pin to SVIN by inserting the JP3 jumper into the rightmost position. terminals on the left-side of the board. Do not hot- + + – – – + – + + VS + LOAD – – Figure 1. Proper Measurement Equipment Setup GND VIN Figure 2. Scope Probe Placement for Measuring Output Ripple 1 5 4 3 2 1 E7 PGood 9 Ith 10 SD/RT 2 Rs2 1M Rset 324K JP3 3 4.7M Rfb3 412K, 1% Rfb2 698K, 1% JP2 Rfb4 280K, 1% Opt. 3.3V E4 GND OFF ON E6 RPG RFB1 RSW CFFW C1 COUT2 RC CC GND COUT1 CIN2 CIN1 L1 U1 C 1.8V 2.5V E5 GND B Cout3 0.1uF 1 7 Rsd 2 E2 Rfb1 887K, 1% 1% Rfb5 Opt. R1 10K SYNC /MODE 6.3V Cffw 10pF Opt. Cc 1000pF Burst Mode C C1 Opt. Cout2 1uF 2 PGND Sy/Mode Rc 16.2K 1 2 SGND Cbyp Opt. Rsw Opt. 8 1 Vfb 1 SVin 4 PGood 7 3 JP1 8 0 Rs1 1M Pulse-skip 3 100K 3 Rfilt 2.2uH D1 Cout1 22uF Opt. 6 Cin1 10uF 6.3V Cin2 1uF Opt. Vout 3.3V/2.5V/1.8V 1.25A Cout4 Opt. E3 4 SW 5 Cin3 Opt. PVin 1 6 Rpg L1 2 Vin E1 VIN 2.65V-5.5V Cin4 47uF 16V D U1 LTC3411EMS 5 D B RSET PCB SILKSCREEN CONTRACT NO. APPROVALS DRAWN A June Wu DATE 6/28/01 TECHNOLOGY TITLE ENGINEER Tom Gross A LTC3411EMS CHECKED APPROVED 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 Buck Regulator: 2.65V-5.5V->1.8V, 2.5V, or [email protected](max) 6/28/01 SIZE CAGE CODE DESIGNER DWG NO REV A DEMO DC441A Monday, March 11, 2002 5 4 3 SCALE: 2 FILENAME: SHEET 1 1 OF 1 Bill Of Material Demo Bd. #441A Linear Technology Corporation LTC3411EMS 6/17/2005 11:57 AM Item Qty Reference 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 0 1 1 1 1 0 1 1 0 0 7 2 1 3 1 1 1 1 1 1 1 0 1 1 1 0 2 1 1 1 1 1 Cbyp,Cout2,Cin2 (OPT) Cc Cffw Cout1 Cin1 Cout4,Cin3 (OPT) Cout3 Cin4 C1 (OPT) D1 (OPT) E1-E7 JP1,JP3 JP2 JP1,JP2,JP3 L1 Rc R1 Rfb1 Rfb2 Rfb3 Rfb4 Rfb5 (OPT) Rfilt Rpg Rset Rsw (OPT) Rs1,Rs2 Rsd U1 Part Description CAP., 0603 CAP., X7R, 1000pF, 25V, 20% 0402 CAP., NPO, 10pF, 50V, 10% 0402 CAP., X5R, 22uF, 6.3V, 10% 1210 CAP., X5R, 10uF, 6.3V, 10% 1206 CAP., 6032, 7343 CAP., X7R, 0.1uF, 16V, 20% 0603 CAP., TANT., 47uF, 16V, 20% 6032 CAP., 402 DIODE, SMA TESTPOINT, TURRET, .094" 0.079 SINGLE ROW HEADER 3 PIN 0.079X4 DOUBLE ROW HEADER SHUNT, INDUCTOR, 2.2uH D52LC RES.,CHIP, 16.2K, 1/16W, 5%, 0402 RES.,CHIP, 10K, 1/16W, 5%, 0402 RES.,CHIP, 887K, 1/16W, 1% 0402 RES.,CHIP, 698K, 1/16W, 1% 0402 RES.,CHIP, 412K, 1/16W, 1% 0402 RES.,CHIP, 280K, 1/16W, 1% 0402 RES., 1% 0402 RES.,CHIP, 0, 1/16W, 0402 RES.,CHIP, 100K, 1/16W, 5% 0402 RES.,CHIP, 316K, 1/16W, 1% 0402 RES., 0402 RES.,CHIP, 1M, 1/16W, 5% 0402 RES.,CHIP, 4.7M, 1/16W, 5% 0402 I.C., LTC3411, MS10 PRINTED CIRCUIT BOARDS STENCIL S/F 6-Boards to Alan 3/15/02 Page 1 - of - 1 Manufacture / Part # AVX, 04023C102MAT AVX, 04025A100KAT MURATA, GRM32DR60J226KA01 MURATA, GRM31CR60J106KC01 AVX, 0603YC104MAT AVX, TAJC476M016R MILL-MAX, 2501-2 COMM CON, 2802S-03-G1 COMM CON, 2202S-08-G1 COMM CON, CCIJ2MM-138G TOKO, A914BYW-2R2M AAC, CR05-1622FM AAC, CR05-103JM AAC, CR05-8873FM AAC, CR05-6983FM AAC, CR05-4123FM AAC, CR05-2803FM AAC, CJ05-000M AAC, CR05-104JM AAC, CR05-3163FM AAC, CR05-105JM AAC, CR05-475JM LINEARL, LTC3411EMS DEMO BOARD DC441A STENCIL DC441A S / Frame, #10679, @ Flairis