RT9221
Programmable Synchronous PWM Buck Converter with
1.5V/2.5V Dual Low Dropout Linear Regulator Controller
General Description
The RT9221 integrates a PWM controller and two
low-dropout linear regulators into a single chip. The
PWM controller provides the CPU core voltage
controlled by a 5-bit DAC and the linear section
regulates power for GTL bus, clock driver or other
circuits on motherboards. The PWM controller
provides an adjustable Intel-compatible 1.3V~3.5V
output voltage. The synchronous N-MOSFET driver
with 200 KHz switching frequency optimizes the
efficiency, device size, and cost built-in over鈥搗oltage
and current-limiting protection prevent the CPU from
damage. Power-good signal is sent when the core
voltage is within
卤10%
of the setting point.
The linear section is a low dropout regulator which
drives low cost NPN transistors to supply the 1.5V
and 2.5V regulated output power.
Features
Provides 3 Regulated Voltages
N-MOSFET
Power-good,
Driver
for
High
and
Efficiency
Current-
Switching Section
Over-voltage,
limiting Protection for Switching Section
1.5V and 2.5V Fixed Output Voltage for Linear
Section
Linear Section Uses Low Cost NPN Transistor
as Power Device
TTL-compatible
Voltage
5-bit
DAC
Core
Output
Applications
Power Supply for Pentium, Pentium Pro
Pentium II
Alpha
TM
TM
TM
,
, Power PC
TM
, K6
TM
, 6脳86
TM
, and
Microprocessors
High-power 5V to 3.xV DC-DC Regulators
Low-voltage Distributed Power Supplies
Programmable Power Supplies
Ordering Information
RT9221
Package type
S : SOP-24
Operating temperature range
C: Commercial standard
Pin Configurations
Part Number
RT9221CS
(Plastic SOP-24)
Pin Configurations
TOP VIEW
GND
GATE1
LDOS1
LDOS2
1
2
3
4
GATE2
23
LDOV
22
VID0
24
VCC
5
OVP
6
PGOOD
7
CSN
8
CSP
9
PGNDH
10
DH
11
PGNDL
12
VID1
20
VID2
19
VID3
18
VID4
17
VSEN
16
SHDN
15
BSTH
14
BSTL
13
DL
21
DS9222-05 May 2001
www.richtek-ic.com.tw
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