IRDC3138EVAL IRU3138 EVALUATION BOARD USER GUIDE DESCRIPTION SPECIFICATION DATA The IRU3138 controller IC is designed to provide a low cost synchronous Buck regulator for voltage tracking applications such DDR memory and general purpose on-board DC to DC converter. Modern micro processors combined with DDR memory, need high-speed bandwidth data bus which requires a particular bus termination voltage. This voltage will be tightly regulated to track the half of chipset voltage for best performance. The IRU3138 together with two N-channel MOSFETs, provide a low cost solution for such applications. This device features a programmable frequency set from 200KHz to 400KHz, under-voltage lockout for both Vcc and Vc 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. Switcher: Vc = 12V Vcc =VIN =5V VOUT = 1.6V IOUT = 12A DVOUT = 50mV FS = 400KHz INPUT/OUTPUT CONNECTIONS The following is the input/output connections: Inputs: JP1: Input (+5V) and GND JU1: Vcc/Vc The connection points is shown in Figure 1. Connect the power supply cables according to this figure, minimize wire lengths to reduce losses in the wire. Test point J1 provides easy connections for oscilloscope voltage probe to monitor the output voltage. Outputs: JP2: VOUT (+1.6V) JP3: Gnd Other Connections: J1: Scope connection for Vout Rev. 1.3 03/29/04 www.irf.com 1 IRDC3138EVAL Power Supply CONNECTION DIAGRAM Power Supply 6A Supply +12V Gnd +5V Gnd Load 0 - 15A Figure 1 - Connection diagram of evaluation-board for IRU3138. 2 www.irf.com Rev. 1.3 03/29/04 IRDC3138EVAL LAYOUT The top side (component) layer for IRU3138 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 IRU3138. Rev. 1.3 03/29/04 www.irf.com 3 IRDC3138EVAL SCHEMATIC 1 2 3 4 D D JP1 + C1 +5V +5V R15 INPUT L1 D1 R14 VC C20 N10 C23 + GND + JU1 N15 + C19 R16 R2 C8 VREF 3 VP 2 SS R1 RT 11 COMP 12 HDrv Vp NC SS U1 IRU3138 NC 9 HDRV R3 + C + VD C6 J1 Q1 VGH 1 L2 D3 NC1 14 JP2 N25 + VO VO NC2 5 6 Rt LDrv Comp PGnd 8 Gnd 7 LDRV C9 VGL C10 N50 + C11 + C21 + C22 C12 OUTPUT + Q2 R5 1 VO D2 R6 2 R4 13 Vref C2 2 Vcc VDDQ R13 C18 C5 3 4 VREF1 C4 Vc C 10 C7 3 VCC C3 R12 1 Fb JP3 + GND +C24 FB B +C25 OUTPUT C13 C14 N30 R9 C15 R7 R8 C16 R10 B GND C17 N40 R11 A Title Size Orcad A Date: File: 1 2 A IRU3138 Number Revision V2R0 JE3138S-V2R0 5-Sep-2003 C:\Old_Drv\pcb\PCB_last2.ddb 3 Sheet of Drawn By: 4 Figure 3 - Schematic of evaluation-board for IRU3138. 4 www.irf.com Rev. 1.3 03/29/04 IRDC3138EVAL BILL OF MATERIAL Ref Desig Q1 Q2 U1 D3 L1 L2 C1,2,18,20 C11,21,22 C8 C3,4,6,12 C7 C9 C3,C6,C12 R9 R6 R8,R11 R2,3,4,5,15 R1,7,10,12, 13,14,16 Description MOSFET MOSFET Controller Diode Inductor Inductor Cap, Poscap Cap, Poscap Cap, Ceramic Cap, Ceramic Cap, Ceramic Cap, Ceramic Cap, Ceramic Resistor Resistor Resistor Resistor Resistor Value Qty Part# 20V, 11mV 1 IRLR3715Z 20V, 6mV 1 IRFR3711Z Synchronous PWM 1 IRU3138 Fast Switching 1 BAT54S 1mH, 10A 1 D03316P-102HC 1.1mH, 16A 1 ETQP6F1R1BFA 150mF, 6.3V 4 6TPC150M 330mF, 6.3V, 40mV 3 6TPC330M 0.1mF, Y5V, 25V 1 ECJ-2VF1E104Z 1mF, X7R, 25V 3 ECJ-3YB1E105K 100pF, 50V 1 ECJ-2VB1H101J 470pF, X7R 1 ECJ-2VB2D471K 1mF, Y5V, 16V 3 ECJ-2VF1C105Z 17.8K, 5% 1 4.7V, 5% 1 1K, 1% 2 0V 4 Not Used 7 Manuf IR IR IR IR Coilcraft Panasonic Sanyo Sanyo Panasonic Panasonic Panasonic Panasonic Panasonic Web site (www.) irf.com coilcraft.com maco.panasonic.co.jp sanyo.com/industrial maco.panasonic.co.jp 5 C7,10,13,14 Capacitor 16,17,19,23 24,25 D2 Diode Not Used 10 Not Used 1 TYPICAL OPERATING CHARACTERISTICS Vin=5.0V, Vout=1.6V 92 Efficiency (%) 90 88 86 84 82 80 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Output Current (A) Start-up time Ch2:VC, Ch3:SS pin, Ch4:Vout Efficiency Rev. 1.3 03/29/04 www.irf.com 5 IRDC3138EVAL TYPICAL OPERATING CHARACTERISTICS Shut Down the output by pulling down the soft-start pin Ch1: HDrv, Ch2:LDrv, Ch3: SS pin Output Voltage Ripple @ 15A Ch1:Output, Ch4:Iout (5A/Div) Transient response @ Iout=15A Ch1: Output, Ch4:Iout (5A/Div) 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 specifications subject to change without notice. 02/01 6 www.irf.com Rev. 1.3 03/29/04