US3022
4 BIT PROGRAMMABLE SYNCHRONOUS BUCK
PLUS FOUR LDO CONTROLLER
PRELIMINARY DATASHEET
FEATURES
Provides Single Chip Solution for Vcore,
GTL+ ,AGP Bus, 1.8V , 2.5V
Automatic Voltage Selection for AGP slot's
Vddq supply
4 Linear regulator controller on board to
achieve lowest system cost solution
Standby Vref provides reference for the ACPI
regulators
Designed to meet Intel Latest VRM specifica-
tion for next generation micrprocessors
On board DAC programs the output voltage
from 1.3V to 2.05V
On board resistor dividers provides lowest
component count
Loss less Short Circuit Protection for all
outputs
Synchronous operation allows maximum
efficiency
Patented architecture allows fixed frequency
operation as well as 100% duty cycle during
dynamic load
Soft Start
High current totem pole driver for direct
driving of the external Power MOSFET
Power Good function Monitors all Outputs
OVP Circuitry Protects the Switcher Output
and generates a Fault output
DESCRIPTION
The US3022 is the first controller IC with five controller in
one package specifically designed to meet Intel specifi-
cation for next generation microprocessor applications
requiring multiple on board regulators .
The US3022 pro-
vides a single chip controller IC for the Vcore , 4
LDO controllers, one with the automatic select pin
that connects to the TYPE DETECT pin of the AGP
slot for the AGP Vddq supply, one for GTL+ , the
other for the 1.8V chip set regulator as well as 2.5V
for the clock as required for the next generation
PC applications. The US3022 typically uses Bipolar
transistors for Vout3(1.5V) and Vout4(1.8V) and Vout5
however if Vaux pin is connected to 12V, then
MOSFETs can also be used as external pass ele-
ments. No external resistor divider is necessary for
any of the regulators.
The switching regulator feature
a patented topology that in combination with a few ex-
ternal components as shown in the typical application
circuit ,will provide well in excess of 20A of output cur-
rent for an on- board DC/DC converter while automati-
cally providing the right output voltage via the 5 bit inter-
nal DAC .The US3022 also features,
loss less current
sensing for both switcher by using the Rds-on of
the high side Power MOSFET as the sensing resis-
tor, an output under voltage shutdown that detects
short circuit condition for the linear outputs and
latches the system 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 pro-
grammed window.
APPLICATIONS
Total Power Soloution for Next Generation Intel
Processor application
TYPICAL APPLICATION
5V
3.3V
LINEAR
CONTROL
SWITCHER
CONTROL
Vout1
Vout2
US3022
LINEAR
CONTROL
Vout3
LINEAR
CONTROL
LINEAR
CONTROL
Vout4
3022app3-1.0
Vout5
PACKAGE ORDER INFORMATION
Ta (°C)
0 TO 70
Rev. 1.0
11/2/99
Device
US3022CW
Package
28 pin Plastic SOIC WB
4-1
UNISEM [ UNISEM ]
