QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A SYNCHRONOUS STEP-DOWN DC/DC CONVERTER LTC3610EWP DESCRIPTION Demonstration circuit DC1129A is a synchronous step down converter featuring the LTC®3610, the high efficiency, high density DC/DC regulator. The input voltage range is from 4.5V to 24V. The output voltage is jumper selectable from 1.2V to 2.5V. The rated load current is 12A. The regulator includes the controller and power MOSFETs in the 9mm by 9 mm QFN package. The constant on time valley mode current control structure delivers very low duty cycle with excellent load transient response. The MSFET RDS(on) sensing eliminates external sensing resistor and improves supply efficiency. Discontinuous mode operation and continuous mode at light load is also jumper selectable. A forced continuous control reduces noise and RF interference while discontinuous control provides high efficiency at light loads. Design files for this circuit board are available. Call the LTC Factory. , LTC and LT are registered trademarks of Linear Technology Corporation. Table 1. Performance Summary (TA = 25°C) PARAMETER CONDITION VALUE Minimum Input Voltage 4.5V Maximum Input Voltage 24V Output Voltage VOUT Jumper selectable (open for 0.6V) 1.2V, 1.5V, 1.8V, 2.5V ± 2% Maximum Continuous Output Current De-rating is necessary for certain VIN, VOUT, and thermal conditions, see datasheet 12ADC Operating Frequency Programmable 750kHz Efficiency VIN=12V, VOUT =1.5V, IOUT =12A 83%, See Figure 3 Load Transient VIN=12V, VOUT =1.5V See Figure 5 QUICK START PROCEDURE Demonstration circuit DC1129A is easy to set up to evaluate the performance of the LTC3610. Please refer to Figure 1 for proper measurement equipment setup and follow the procedure below: 1. Place jumpers in the following positions for a typical 1.5VOUT application: Vout Select RUN FCB 1.5V ON CCM Preliminary 2. With power off, connect the input power supply, load and meters as shown in Figure 1. Preset the load to 0A and Vin supply to be less than 24V. 3. Turn on the power at the input. The output voltage should be 1.5V ± 2%. 4. Once the proper output voltage is established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. Output ripple should be measured across the output bulk capacitor as shown in Figure 2. 5. For optional load transient test, apply adjustable pulse signal between IOSTEP CLK and GND pins. Pulse amplitude sets the current 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A SYNCHRONOUS STEP-DOWN DC/DC CONVERTER – Iout A – Load 0 -12A + V Vout + Vin – – – + V A + – + Iin nector J6 (5mV/A). Output voltage transient response should be measured at J5 with a BNC cable. + step. The pulse signal should have very small duty cycle (<5%) to limit the thermal stress on the transient load circuit. The output transient current can be monitored at BNC con- Optional 5V Bias Figure 1. Test Setup of DC1129A (EXTVCC Bias Supply is Optional) + Input or Output Capacitor Figure 2. Scope Probe Placements for Measuring Input or Output Ripple. Preliminary 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A SYNCHRONOUS STEP-DOWN DC/DC CONVERTER Efficiency vs. Load Current W/ 12Vin 90% Efficiency (%) 80% 70% Vo=1.2V Vo=1.5V 60% Vo=1.8V Vo=2.5V 50% 0 2 4 6 8 10 12 14 16 Load Current (A) Figure 3. Measured Supply Efficiency with Different VIN and VOUT Figure 4. Thermal image of DC1129 Vin = 12V Vout =1.5V Iout = 12A Tambient = 25°C, No airflow Cross 1: MOSFETs Cross 2: Inductor Preliminary 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A SYNCHRONOUS STEP-DOWN DC/DC CONVERTER Istep 4A/DIV Cout (AC) 100mV/DIV Vin = 12V Vout =1.5V 3A to 9A LOAD STEP Cout = 2 X 22uF ceramic, X5R, 0805, 2X100uF ceramic, X5R, 1812 Figure 5. Measured Load Transient Response (3-9A Step, 25% to 75%) Preliminary 4 R1 OPT CSS 0.1UF INTVCC JP2 1.2V JP3 1.5V JP4 1.8V JP5 2.5V R9 60.4K R10 40.2K R11 30.1K R12 19.1K 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 C6 R8 OPT 137K SGND SGND VON PGOOD VRNG ITH FCB SGND ION SGND VFB EXTVCC SGND SGND SGND SGND PVIN SW PGND PVIN PVIN PVIN PVIN PVIN SW SW SW SW SW SW SW SW PGND PGND PGND 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 EXTVCC E2 EXTVCC INTVCC C7 OPT C8 4.7UF 16V 0805 + CIN3 CIN1 CIN2 10UF 35V 1206 CIN4 CIN5 1210 OPT 150UF 35V SANYO CIN6 CIN7 1206 OPT J2 E3 PGND 35ME150WXV L1 0.47UH TOKO FDV0630 VOUT CO1 CO2 + 100UF 6.3V 1812 CO3 CO4 330UF 6.3V 7343 OPT E5 J3 CO6 CO5 22UF 6.3V 0805 E6 R13 1 Q1 SUD50N03 1 C9 1UF 35V R16 10K VOUT C10 4.7UF 6.3V J5 VOUT J6 IOSTEP R5 0.005 2512 E8 DYNAMIC TRANSIENT CIRCUIT NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE 0603. 2. INSTALL SHUNT ON JP1 PINS 1 AND 2, JP3. 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 CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. CONTRACT NO. APPROVALS DRAWN: TECHNOLOGY KIM T. CHECKED: APPROVED: ENGINEER: MANJING X. DESIGNER: VOUT 12A MAX. J4 PGND 3 E7 C5 47PF 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 U1 LTC3610CUP 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 SGND R3 11K VIN E1 4.5V-24V VIN 2 VOUT SELECT R7 60.4K 2 RUN/SS VOUT PGOOD J1 R14 SGND SGND RUN/SS BOOST NC NC SW PVIN PVIN PVIN PVIN PVIN PVIN PVIN PVIN PVIN C2 0.01UF C3 100PF C4 R6 1000PF 7.5K SW SGND Preliminary E4 D1 C1 CMDSH-3 0.22UF 16V 1 BOOST R2 OPT R4 100K PGOOD 3 2 1 2 SGND SGND SVIN SVIN SVIN INTVCC INTVCC INTVCC SW PGND PGND PGND PGND PGND PGND PGND PGND PGND INTVCC INTVCC IOSTEP CLK 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: SCHEMATIC HIGH INPUT VOLTAGE AND HIGH CURRENT DENSITY STEP-DOWN CONVERTER SIZE A DATE: DWG NO. DC1129A-1 * LTC3610CUP Tuesday, March 27, 2007 SHEET REV A-1 1 OF 1 5 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A SYNCHRONOUS STEP-DOWN DC/DC CONVERTER DCM JP6 CCM FCB DC1129A Schematic RUN/SS 1 ON 2 JP1 3 OFF QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A SYNCHRONOUS STEP-DOWN DC/DC CONVERTER DC1129A BOM Item Qty Reference Part Description Manufacturer / Part # REQUIRED CIRCUIT COMPONENTS 1 2 3 2 1 2 CIN1,CIN2 CIN3 CO1,CO2 CAP., X5R, 10UF 35V, 1206 CAP., ELECTROLYTIC, 150UF 35V CAP., X5R, 100UF 6.3V 20%, 1812 TAIYO YUDEN, GDK316BJ106ML SANYO, 35ME150WXV+TS TDK, C4532X5R0J107MT 4 5 6 2 1 1 CO5,CO6 CSS C1 CAP., X5R, 22UF 6.3V 20%, 0805 CAP., X7R, 0.1UF 25V 20%, 0603 CAP., X7R, 0.22UF 16V 20%, 0603 TDK, C2012X5R0J226M TDK, C1608X7R1E104M TDK, C1608X7R1C224M 7 8 9 1 1 1 C2 C3 C4 CAP., X7R, 0.01UF 25V 20%, 0603 CAP., NPO, 100PF 50V, 0603 CAP., NPO, 1000PF 50V, 0603 TDK, C1608X7R1E103M AVX, 06035A101KAT2A AVX, 06035A102KAT2A 10 11 12 1 1 1 C5 C8 C9 CAP., NPO, 47PF 50V 10%, 0603 CAP., X5R, 4.7UF 16V, 0805 CAP., X5R, 1UF 35V 20%, 0603 AVX, 06035A470KAT2A TDK, C2012X5R1C475M TAIYO YUDEN, GMK107BJ105MA-T 13 14 15 1 1 0 D1 L1 L1 DIODE,SCHOTTKY, SOD323 IND, 0.47UH, L-TOKO-FDV0630 IND, 0.36UH, L-TOKO-FDH1040 CENTRAL SEMI., CMDSH-3 TOKO, FDV0630-R47M=P3 TOKO, FDH1040B-R36M=P3 16 17 18 19 20 21 1 1 1 1 1 1 R3 R6 R7 R8 R10 R13 RES., Chip 11K 1/16W 5%,0603 RES., Chip 7.5K 1/16W 1%,0603 RES., Chip 60.4K 1/16W 1%,0603 RES., Chip 137K 1/16W 1%,0603 RES., Chip 40.2K 1/16W 1%,0603 RES., Chip 1 1/16W 5%,0603 AAC, CR16-113JM AAC, CR16-7501FM AAC, CR16-6042FM AAC, CR16-1373FM AAC, CR16-4022FM AAC, CR16-1R0JM 22 23 1 1 R14 U1 RES., Chip 2 1/16W 5%,0603 I.C., LTC3610EWP, QFN64UP AAC, CR16-2R0JM LINEAR TECH., LTC3610EWP OPT ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS 1 2 3 0 0 0 CIN4,CIN5 CIN6,CIN7 CO3,CO4 CAP., 1210 CAP., 1206 CAP., 7343 OPT OPT OPT 4 5 6 0 1 1 C6,C7 C10 Q1 CAP., 0603 CAP., X5R, 4.7UF 6.3V 10%, 0603 XTER, N-CH, 30V, DPAK-TO252AA OPT AVX, 06036D475KAT VISHAY, SUD50N03-10CP 7 8 9 10 11 12 0 0 1 1 1 1 R1 R2 R4 R5 R9 R11 RES., 0603 RES., Chip 39.2K 1/16W 1%,0603 RES., Chip 100K 1/16W 5%,0603 RES., Chip 0.005 1W 1%,2512 RES., Chip 60.4K 1/16W 1%,0603 RES., Chip 30.1K 1/16W 1%,0603 OPT AAC, CR16-3922FM AAC, CR16-104JM PANASONIC, ERJM1WSF5M0U AAC, CR16-6042FM AAC, CR16-3012FM 13 14 1 1 R12 R16 RES., Chip 19.1K 1/16W 1%,0603 RES., Chip 10K 1/16W 5%,0603 AAC, CR16-1912FM AAC, CR16-103JM HARDWARE FOR DEMO BOARD ONLY 1 8 E1,E2,E3,E4,E5,E6,E7,E8 TESTPOINT, TURRET, 0.064" MILL-MAX, 2308-2 2 3 2 4 JMP, 3PIN 1 ROW .079CC JMP, 2PIN 1 ROW .079CC SAMTEC, TMM-103-02-L-S SAMTEC, TMM-102-02-L-S 4 5 6 7 3 4 2 4 JP1,JP6 JP2,JP3,JP4,JP5 SHUNTS ON JP1&JP6 PINS 1&2, AND JP3 J1,J2,J3,J4 J5,J6 MTG 4 CORNERS SHUNT, .079" CENTER JACK, BANANA,KEY-575 CONN, BNC, 50 OHMS STAND-OFF, NYLON (SNAP ON), 0.50" TALL SAMTEC, 2SN-BK-G KEYSTONE, 575-4 CONNEX, 112404 KEYSTONE, 8833 Preliminary 6