Data Sheet No. PD94145
IRU3021M
5-BIT PROGRAMMABLE SYNCHRONOUS BUCK
PLUS TRIPLE LDO CONTROLLER
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 V
DDQ
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(V
DDQ
),
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 R
DS(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.
FEATURES
Provides single chip solution for Vcore, GTL+,
AGP bus, and 1.8V
Automatic voltage selection for AGP slot V
DDQ
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
APPLICATIONS
Total Power Solution for next generation Intel
processor application
TYPICAL APPLICATION
5V
3.3V
LINEAR
CONTROL
SWITCHER
CONTROL
Vout1
Vout2
IRU3021M
LINEAR
CONTROL
LINEAR
CONTROL
Vout4
3021Mapp3-1.1
Vout3
Figure 1 - Typical application of the IRU3021M.
PACKAGE ORDER INFORMATION
T
A
(!C)
0 To 70
Rev. 1.4
07/24/01
DEVICE
IRU3021MCW
PACKAGE
28-Pin Plastic SOIC WB
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