Data Sheet No. PD94250 IRU3038 SYNCHRONOUS PWM CONTROLLER FOR TERMINATION POWER SUPPLY APPLICATIONS PRELIMINARY DATA SHEET FEATURES DESCRIPTION Synchronous Controller in 14-Pin Package The IRU3038 controller IC is designed to provide a low Operating with single 5V or 12V supply voltage cost synchronous Buck regulator for voltage tracking 200KHz to 400KHz operation set by an external applications such DDR memory and general purpose resistor on-board DC to DC converter. Modern micro processors Soft-Start Function combined with DDR memory, need high-speed bandwidth Fixed Frequency Voltage Mode data bus which requires a particular bus termination volt- 500mA Peak Output Drive Capability age. This voltage will be tightly regulated to track the Uncommitted Error Amplifier available for DDR half of chipset voltage for best performance. The IRU3038 voltage tracking application together with dual N-channel MOSFETs such as IRF7313, 1.25V Reference Voltage provide a low cost solution for such applications. This Protects the output when control FET is shorted device features a programmable frequency set from 200KHz to 400KHz, under-voltage lockout for both Vcc APPLICATIONS and Vc supplies, an external programmable soft-start DDR memory source sink Vtt application function as well as output under-voltage detection that Low cost on-board DC to DC such as latches off the device when an output short is detected. 5V to 3.3V, 2.5V or 1.8V Graphic Card Hard Disk Drive TYPICAL APPLICATION 5V 12V L1 VDDQ 1uH C1 (2.5V) C2 C3 C4 0.1uF 1uF 10TPB100M, 47uF 100uF, 55mV R1 Vcc Vc DDR VREF 1K Q1 Memory HDrv VP 1/2 of IRF7313 D1 L2 R2 BAT54 SS U1 Vtt 1K or 1N4148 D03316P-103, 10uH, 3.9A C5 1.25V 3A IRU3038 Q2 0.1uF LDrv C6 1/2 of IRF7313 2x 6TPB150M, PGnd 150uF, 55mV Rt Comp C7 Fb 2200pF Gnd R3 33K Figure 1 - Typical application of IRU3038 when Vtt tracks the VDDQ. PACKAGE ORDER INFORMATION TA (C) DEVICE PACKAGE 0 To 70 IRU3038CF 14-Pin Plastic TSSOP (F) 0 To 70 IRU3038CS 14-Pin Plastic SOIC NB (S) Rev. 2.0 www.irf.com 1 09/12/02IRU3038 ABSOLUTE MAXIMUM RATINGS Vcc Supply Voltage .................................................. 25V Vc Supply Voltage ..................................................... 30V (not rated for inductive load) Storage Temperature Range ...................................... -65C To 150C Operating Junction Temperature Range ..................... 0C To 125C PACKAGE INFORMATION 14-PIN PLASTIC TSSOP (F) 14-PIN PLASTIC SOIC (S) 14 Fb 1 14 NC Fb 1 NC V 13 VP 2 13 SS P 2 SS VREF 3 12 Comp VREF 3 12 Comp Vcc 4 11 Rt Vcc 4 11 Rt NC 5 10 Vc 5 10 Vc NC LDrv 6 9 HDrv 6 9 LDrv HDrv Gnd 7 8 PGnd 7 8 Gnd PGnd uJA=888C/W uJA=1008C/W ELECTRICAL SPECIFICATIONS Unless otherwise specified, these specifications apply over Vcc=5V, Vc=12V and TA=0 to 70C. Typical values refer to TA=25C. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient temperature. PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS Reference Voltage VREF Voltage VFB 1.225 1.250 1.275 V LREG Fb Voltage Line Regulation 5<Vcc<12 0.2 0.35 % UVLO UVLO Threshold - Vcc UVLO Vcc Supply Ramping Up 4 4.2 4.4 V UVLO Hysteresis - Vcc 0.25 V UVLO Threshold - Vc UVLO Vc Supply Ramping Up 3.1 3.3 3.5 V UVLO Hysteresis - Vc 0.2 V UVLO Fb UVLO Threshold - Fb Fb Ramping Down 0.4 0.6 0.8 V UVLO Hysteresis - Fb 0.1 V Supply Current Dyn Icc Vcc Dynamic Supply Current Freq=200KHz, CL=1500pF 2 5 8 mA Vc Dynamic Supply Current Dyn Ic Freq=200KHz, CL=1500pF 2 7 10 mA Vcc Static Supply Current ICCQ SS=0V 1 3.5 6 mA ICQ Vc Static Supply Current SS=0V 0.5 1 4.5 mA Soft-Start Section Charge Current SSIB SS=0V -10 -20 -30 mA Rev. 2.0 www.irf.com 2 09/12/02