RT9228
Advanced PWM and Dual Linear Power Controller
General Description
The RT9228 is a 3-in-one power controller optimized
for high-performance microprocessor and computer
applications. The IC integrates a synchronous buck
PWM controller, a linear regulator, and a linear
controller as well as monitoring and protection
functions into a 24-pin SOP package. The PWM
controller regulates the microprocessor core voltage.
The linear regulator provides power for the clock
driver circuit and the linear controller regulates power
for the GTL bus.
The RT9228 features an Intel-compatible, TTL 5-bit
programmable DAC that adjusts the core voltage
from 2.1V to 3.5V in 0.1V increments and from 1.3V
to 2.05V in 0.05V steps. The 5-bit DAC has a typical
鹵1%
tolerance. The linear regulator uses an internal
drive device to provide 2.5V
鹵2.5%
output voltage.
The linear controller drives an external N-channel
MOSFET or a low cost NPN bipolar transistor to
provide 1.5V
鹵2.5%.
The RT9228 monitors all the output voltages. A
Power-good signal is issued when the core voltage is
within
鹵10%
of the DAC setting and the other levels
are above their under-voltage levels. Additional build-
in over-voltage protection for the core output uses
the lower MOSFET to prevent output voltage above
115% of the DAC setting. The PWM over-current
function monitors the output current using the voltage
drop across the upper MOSFET鈥檚 R
DS(ON)
, which
eliminates the need for a current sensing resistor.
Features
3-in-one Regulated Voltages for Microprocessor
Core, Clock, and GTL
Compatible with HIP6018B
Power-good Output Voltage Monitor
Switching section
5-bit DAC Programmable from 1.3V to 3.5V
鹵1%
DAC Accuracy
Fast Transient Response
Full 0% to 100% Duty Cycle Driver
Fixed 200kHz Switching Frequency
Adaptive Non-overlapping Gate Driver
Over-current Monitor Uses MOSFET R
DS(ON)
Over-voltage Protection Uses Lower MOSFET
Linear Section
User-adjustable Linear Regulator Output Voltage
MOSFET or NPN Driving Capability
Ultra Fast Response Speed
Under-voltage Protection
Internal Thermal Shutdown
Applications
Full Motherboard Power Regulation for Computer
Low-voltage Distribution Power Supplies
Pin Configurations
Part Number
RT9228CS
(Plastic SOP-24)
VCC
VID4
VID3
VID2
VID1
VID0
1
2
3
4
5
6
7
Pin Configurations
TOP VIEW
UGATE1
23
PHASE1
22
LGATE1
24
21
20
19
18
17
16
15
Ordering Information
RT9228
Package type
S : SOP-24
Operating temperature range
C: Commercial standard
PGND
OCSET1
VSEN1
FB1
NC
PGOOD
FAULT
8
SS
NC
FB2
VIN2
9
10
11
12
FB3
GATE3
14
GND
13
VOT2
DS9228-03 July 2001
www.richtek.com
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