IRU3021M
1
Rev. 1.5
07/17/02
www.irf.com
TYPICAL APPLICATION
DESCRIPTION
The IRU3021M controller IC is specifically designed to
meet Intel specification for next generation microproces-
sor applications requiring multiple on-board regulators.
The IRU3021M provides a single chip controller IC for
the Vcore, three LDO controllers, one with an automatic
select pin that connects to the Type Detect pin of the
AGP slot for the AGP VDDQ supply, one for GTL+ and
the other for the 1.8V chip set regulator as required for
the next generation PC applications. The IRU3021M uses
N-channel MOSFET as pass transistor for VOUT2(VDDQ),
VOUT3(1.5V) and VOUT4(1.8V). No external resistor di-
vider is necessary for any of the regulators. The switch-
ing regulator feature a patented topology that in combi-
nation with a few external components as shown in the
typical application circuit, will provide well in excess of
20A of output current for an on-board DC/DC converter
while automatically providing the right output voltage via
the 5-bit internal DAC .The IRU3021M also features, loss-
less current sensing for both switcher by using the RDS(ON)
of the high-side power MOSFET as the sensing resistor,
an output under-voltage shutdown that detects short cir-
cuit condition for the linear outputs and latches the sys-
tem off, and a Power Good window comparator that
switches its open collector output low when any one of
the outputs is outside of a pre-programmed window.
Provides single chip solution for Vcore, GTL+,
AGP bus, and 1.8V
Automatic voltage selection for AGP slot VDDQ
supply
Linear Regulator Controller On-Board for 1.8V
Designed to meet Intel latest VRM specification
for next generation microprocessors
On-Board DAC programs the output voltage from
1.3V to 3.5V
Linear Regulator Controller On-Board for 1.5V
GTL+ Supply
Loss-less Short Circuit Protection for all Outputs
Synchronous operation allows maximum effi-
ciency
Patented architecture allows fixed frequency
operation as well as 100% duty cycle during
dynamic load
Minimum Part Count
Soft-Start
High current totem pole driver for direct driving of
the external Power MOSFET
Power Good function monitors all outputs
Over-Voltage Protection Circuitry Protects the
switcher output and generates a Fault output
PACKAGE ORDER INFORMATION
FEATURES
5-BIT PROGRAMMABLE SYNCHRONOUS BUCK
CONTROLLER IC WITH TRIPLE LDO CONTROLLER
APPLICATIONS
Total Power Solution for next generation Intel
processor application
TA (8C) DEVICE PACKAGE
0 To 70 IRU3021MCW 28-Pin Plastic SOIC WB
Data Sheet No. PD94145
Figure 1 - Typical application of the IRU3021M.
LINEAR
CONTROL
LINEAR
CONTROL
SWITCHER
CONTROL
IRU3021M
V
OUT
3
5V
V
OUT
1
V
OUT
4
LINEAR
CONTROL
V
OUT
2
3.3V
