US3018 Datasheet, PDF (1/17 Pages) UNISEM – 5 BIT PROGRAMMABLE SYNCHRONOUS BUCK PLUS LDO CONTROLLER AND 200mA LDO ON BOARD

US3018
5 BIT PROGRAMMABLE SYNCHRONOUS BUCK PLUS
FEATURES
LDO CONTROLLER AND 200mA LDO ON BOARD
PRELIMINARY DATASHEET
DESCRIPTION
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
APPLICATIONS
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.
Total Power Soloution for Pentium II processor
application
TYPICAL APPLICATION
5V
3.3V
Vout3
US3018 SWITCHER1
CONTROL
LINEAR
LINEAR
CONTROL REGULATOR
Vout1
3018app3-1.1
Vout2
Notes: Pentium II is trade mark of Intel Corp.
PACKAGE ORDER INFORMATION
Ta (°C)
0 TO 70
Device
US3018CW
Rev. 1.4
12/8/00
Package
24 pin Plastic SOIC WB
4-1