US3018
5 BIT PROGRAMMABLE SYNCHRONOUS BUCK PLUS
LDO CONTROLLER AND 200mA LDO ON BOARD
FEATURES
Provides Single Chip Solution for Vcore, GTL+
& Clock Supply
200 mA On board LDO regulator
Designed to meet the latest Intel specification
for Pentium II™
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 with HICCUP
Synchronous operation allows maximum effi-
ciency
Patented architecture allows fixed frequency
operation as well as 100% duty cycle during
dynamic load
Soft Start
High current totem pole driver for direct driv-
ing of the external Power MOSFET
Power Good function Monitors all Outputs
OVP Circuitry Protects the Switcher Output and
generates a Fault signal
Thermal Shutdown
Logic Level Enable Input
DESCRIPTION
PRELIMINARY DATASHEET
APPLICATIONS
Total Power Soloution for Pentium II processor
application
The US3018 controller IC is specifically designed to meet
Intel specification for Pentium II™ microprocessor ap-
plications as well as the next generation of P6 family
processors.
The US3018 provides a single chip con-
troller IC for the Vcore , LDO controller for GTL+
and an internal 200mA regulator for clock supply
which are required for the Pentium II applications.
These devices feature a patented topology that in com-
bination with a few external components as shown in
the typical application circuit ,will provide in excess of
18A of output current for an on- board DC/DC converter
while automatically providing the right output voltage via
the 5 bit internal DAC. The US3018 also features,
loss
less current sensing for both switchers by using the
Rds-on of the high side Power MOSFET as the sens-
ing resistor, internal current limiting for the clock
supply,
a Power Good window comparator that switches
its open collector output low when any one of the out-
puts is outside of a pre programmed window. Other fea-
tures of the device are ; Undervoltage lockout for both
5V and 12V supplies, an external programmable soft
start function , programming the oscillator frequency via
an external resistor, OVP circuitry for both switcher out-
puts and an internal thermal shutdown.
TYPICAL APPLICATION
5V
US3018
SWITCHER1
CONTROL
Vout1
3.3V
LINEAR
CONTROL
LINEAR
REGULATOR
3018app3-1.1
Vout2
Vout3
Notes: Pentium II is trade mark of Intel Corp.
PACKAGE ORDER INFORMATION
Ta (°C)
0 TO 70
Rev. 1.4
12/8/00
Device
US3018CW
Package
24 pin Plastic SOIC WB
4-1
UNISEM [ UNISEM ]
