US3004/US3005
5 BIT PROGRAMMABLE SYNCHRONOUS BUCK
CONTROLLER IC WITH DUAL LDO CONTROLLER
FEATURES
Meets Latest VRM 8.4 Specification for PIII
Provides Single Chip Solution for Vcore, GTL+
and Clock Supply
On board DAC programs the output voltage
from 1.3V to 3.5V. The US3004/5 remains on for
VID code of (11111).
Dual linear regulator controller on board for
1.5V GTL+ and 2.5V clock supplies
Loss less Short Circuit Protection
Synchronous operation allows maximum effi-
ciency
Patented architecture allows fixed frequency
operation as well as 100% duty cycle during
dynamic load
Min part count, No external Compensation
Soft Start
High current totem pole driver for direct driv-
ing of the external Power MOSFET
Power Good function
DESCRIPTION
The US3004/5 series of controller ICs are specifically
designed to meet Intel specification for Pentium III™
microprocessor applications as well as the next genera-
tion P6 family processors.
The IC provides a single
chip controller IC for the Vcore , GTL+ and clock
supplies required for the Pentium III applications.
These devices feature a patented topology that in
combination with a few external components as shown
in the typical application circuit ,will provide 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 meeting the latest VRM specifica-
tion .These products also feature,
loss less current sens-
ing by using the Rds-on of the high side Power
MOSFET as the sensing resistor,
a Power Good win-
dow comparator that switches its open collector output
low when the output is outside of a
±10%
window. Other
features of the device are ; Undervoltage lockout for both
5V and 12V supplies, an external programmable soft
start function as well as programming the oscillator fre-
quency by using an external capacitor.
APPLICATIONS
Pentium III & next generation processor DC to DC
converter application
Low cost Pentium with AGP
TYPICAL APPLICATION
L1
L2
Q1
C5
C13
C3
R2
R3
R13
R1
C7
R12
Q2
R4
C10
5V
Vout 3
3.3V
C4
C6
R10
8
CS+
9
HDrv
7
CS-
11
LDrv
10
Gnd
14
Vfb3
Lin1 2
Q3
C11
12
V12
1 Ct
C1
13 SS
C2
D4
15
D3
16
D2
17
D1
18
D0
19
PGd
6
Vfb2
4
5
V5
R7
R11
C15
Vfb1 3
Lin2
20
Q4
C9
R14
3004app2-1.9
Vout 1
12V
US3004
R8
Vout 2
C12
VID4
VID3
VID2
VID1
VID0
3.3V
R5
R6
R9
C14
R15
Power Good
C8
Notes: Pentium III is trade mark of Intel Corp.
PACKAGE ORDER INFORMATION
Ta (°C)
0 TO 70
0 TO 70
Device
US3004CW
US3005CW
Package
20 pin Plastic SOIC WB
20 pin Plastic SOIC WB
2.5V Output Voltage
Adjustable
Fixed
Rev. 1.2
12/8/00
4-1
UNISEM [ UNISEM ]
