IRDC3637EVAL IR3637 EVALUATION BOARD USER GUIDE DESCRIPTION The IR3637 controller IC is designed to provide a low cost synchronous Buck regulator for on-board DC to DC applications in a small 8-pin SOIC. The output voltage can be precisely regulated using the internal 0.8V reference voltage for low voltage applications. The IR3637 operates at a fixed internal 400KHz switching frequency to reduce the component size. The device features under-voltage lockout for both input supplies, an external programmable soft-start function as well as output under-voltage detection that latches off the device when an output short is detected. The reference board is designed for 1.8V output using +5V and +12V supplies. This will demonstrate the main features of IC. This user guide contains the schematic and bill of materials, the design guidelines are described in data sheet. SPECIFICATION DATA Vc = 12V Vcc=Vin=5V Vout=1.8V Iout =7A Output Ripple = 50mV Fs = 400KHz INPUT / OUTPUT CONNECTIONS The connection points are shown in Figure1. Connect the power supply The following is the input / output connections: cables according to this figure, Inputs: minimizing wire lengths to reduce JP1: Input (+5V) and GND losses in the wire. Test points J1 and JU1: Vc J2 provide easy connection for Outputs: oscilloscope voltage probe to monitor JP2: Vout (+1.8V) and GND the inductor points and output voltage. Other Connections: J1: Scope connection for Vout J2: Scope connection for Inductor Point PACKAGE INFORMATION Rev1.0 4/29/2005 Fb 1 8 SS/SD Vcc 2 7 Comp LDrv 3 6 Vc Gnd 4 5 HDrv 1 IRDC3637EVAL CONNECTION DIAGRAM +12V Supply +5V Supply 7A Load Figure 1 – Connection diagram of evaluation board for IR3637 Rev1.0 4/29/2005 2 IRDC3637EVAL LAYOUT The top side (component) layer for IR3637 Eval board is shown in Figure 2. The input capacitors are all located close to the MOSFETs. All the decoupling capacitors, and feedback components are located close to IC. The feedback resistors are tied to the output voltage at the point of regulation. The PCB is 4-layers board, one layer is dedicated to Power GND and the analog GND is kept separated from the PGND and it is connected at a single point. Figure 2 – Top layer of evaluation board for IR3637 Rev1.0 4/29/2005 3 IRDC3637EVAL SCHEMATIC 1 2 4 3 JP1 VIN VIN D D INPUT R4 GND + C8 D1 C9 + VC VC/VCC BAT54SCT R5 N15 JU1 C10 C1 C2 SS 8 Q1 VC VCC C SS HDRV COMP R6 5 HDRV VGH G1 D1 J2 J1 C L1 JP2 3 S2 GND VGL G2 LX + VO VO D2 C12 + D2 C13 C11 OUTPUT + GND 4 MOSFET N_DUAL FB FB D1 N25 LDRV LDRV R7 1 S1 D3 U1 IR3637 COMP 7 C6 6 2 VCC C5 R1 C3 B R8 B C4 R3 R9 R10 C7 N40 R2 Title A Size Orcad A Date: File: 1 2 IR3637 - DUAL SO8 MOSFET Number A Revision JE3637S-V1R0 10-Mar-2005 C:\PCB2\PCB_last6.ddb 3 Sheet of Drawn By: 4 Figure 3 – Schematic of the evaluation board Rev1.0 4/29/2005 4 IRDC3637EVAL BILL OF MATERIAL Ref Desig Description Value Qty Part# Manuf Q1 Dual MOSFET 20V, 13.4mOhm 1 IRF8910 IR U1 Controller Synchronous PWM 1 IR3637 IR D3 Diode Fast Switching 1 BAT54A IR L1 Inductor 1.5uH, 8A, 10 mOhm 1 DO3316P-152 Coilcraft C8,9,12,13 Cap, Poscap 150uF, 6.3V, 40mOhm 4 6TPC150M Sanyo C2,C5 Cap, Ceramic 0.1uF, X7R, 16V 2 ECJ-1VB1C104K Panasonic C1,10,11 Cap, Ceramic 1uF, X5R, 6.3V 3 ECJ-1VB0J105K Panasonic C3 Cap, Ceramic 22pF, NPO, 100V 1 ECJ-1VC2A220J Panasonic C4 Cap, Ceramic 1800pF, X7R, 50V 1 ECJ-1VB1H182K Panasonic R3 Resistor 16K, 1% 1 Any R8 Resistor 1.24K, 1% 1 Any R9 Resistor 1K, 1% 1 Any R2,4,6,7 Resistor 0 Ohm 4 Any R1,5,10 Resistor Not Used 3 C6,7 Capacitor Not Used 2 D1 Diode Not Used 1 J1,J2 Socket Scope probe 2 131-5031-00 Tektronix JP1,JP2 Terminal Wire Connect 2 ED1973-ND Digi-Key JU1 Terminal 2-Pin Header 1 S1012-02-ND Digi-Key Rev1.0 4/29/2005 5 IRDC3637EVAL TYPICAL OPERATING WAVEFORMS Test Conditions: Vcc=Vin=5V, Vc=12V, Vout=1.8V, Iout=0-7A, Ta=Room Temp, No Air Flow. Unless otherwise specified. Figure 4 - Start up waveforms Ch1: Vin=Vcc, Ch2: Vc, Ch3: Vss, Ch4: Vout Figure 6 - Gates waveforms Ch1: Hdrv, Ch2Ldrv,, Ch4:Inductor Current ILoad=5A Rev1.0 4/29/2005 Figure 5 - Start up waveforms Ch1: Vin=Vcc, Ch2: Vc, Ch3: Vss, Ch4: Vout Figure 7 - Gates waveforms Ch1: Hdrv, Ch2Ldrv,, Ch3:Inductor Point ILoad=5A 6 IRDC3637EVAL TYPICAL OPERATING WAVEFORMS Test Conditions: Vcc=Vin=5V, Vc=12V, Vout=1.8V, Iout=0-7A, Ta=Room Temp, No Air Flow. Unless otherwise specified. Figure 8 - Shutdown by shorting the SS pin Ch1: Hdrv, Ch2Ldrv,, Ch3:SS ILoad=5A Figure 10 - Load Transient (0-5A) Ch1: Vout, Ch4: Step Load Current Rev1.0 4/29/2005 Figure 9 - Output Voltage Ripple Ch1: Vout, Ch4: Inductor Current ILoad=5A Figure 11 - Load Transient (5-0A) Ch1: Vout, Ch4: Step Load Current IRDC3637EVAL TYPICAL PERFORMANMCE CURVES Test Conditions: Vcc=Vin=5V, Vc=12V, Vout=1.8V, Iout=0-7A, Ta=Room Temp, No Air Flow. Unless otherwise specified. Efficiency (%) Efficiency Vc=12V, Vcc=Vbus=5V, Iout=0-8A, Fs=400KHz 100 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6 7 8 9 Iout (A) Figure 12 - Efficiency using IRF8910 Dual MOSFET This product has been designed and qualified for the Industrial market. IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310)252-7105 TAC FAX: (310) 252-7903 Visit us at www.irf.com for sales contact information Data and specification subject to change without notice. 02/01 Rev1.0 4/29/2005