IRU3073
1
Rev. 1.0
09/17/03
www.irf.com
DESCRIPTION
The IRU3073 controller IC is designed to provide a low
cost synchronous Buck regulator for on-board DC to DC
converter for multiple output applications.
The outputs can be programmed as low as 0.8V for low
voltage applications.
Selectable over-current protection is provided by using
external MOSFET's on-resistance for optimum cost and
performance.
This device features a programmable frequency set from
200KHz to 400KHz, under-voltage lockout for all 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.
Synchronous Controller plus one LDO controller
Current Limit using MOSFET Sensing
Single 5V/12V Supply Operation
Programmable Switching Frequency up to
400KHz
Soft-Start Function
Fixed Frequency Voltage Mode
Precision Reference Voltage Available
Uncommitted Error Amplifier available for DDR
voltage tracking application
PACKAGE ORDER INFORMATION
FEATURES
SYNCHRONOUS PWM CONTROLLER WITH
OVER-CURRENT PROTECTION / LDO CONTROLLER
APPLICATIONS
DDR memory source sink VTT application
Low cost on-board DC to DC such as
12V/5V to output voltages as low as 0.8V
Graphic Card
Hard Disk Drive
Multi-Output Applications
TA (癈)     DEVICE PACKAGE
0 To 70    IRU3073CQ 16-Pin Plastic QSOP NB (Q)
Data Sheet No. PD94699
Figure 1 - Typical application of IRU3073.
TYPICAL APPLICATION
IRU3073
U1
Vcc
VcL
HDrv
LDrv
Fb1
Gnd
Comp
SS/SD
VOUT1
Rt
+5V
OCSet
PGnd
Drv2
Fb2
3.3V
VOUT2
Q1
C2
C11
C9
C1
C6
C7
C10
L2
L1
Q4
Q5
R1
R2
R8
R9
R7
R10
R11
VcH
VP1
VREF
12V
C3
0.1uF
C4
D1