RICHTEK RT9221CS Datasheet
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–voltage
and current-limiting protection prevent the CPU from
damage. Power-good signal is sent when the core
voltage is within ±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.
Ordering Information
Features
z
Provides 3 Regulated Voltages
z
N-MOSFET Driver for High Efficiency
Switching Section
z
Power-good, Over-voltage, and Current-
limiting Protection for Switching Section
z
1.5V and 2.5V Fixed Output Voltage for Linear
Section
z
Linear Section Uses Low Cost NPN Transistor
as Power Device
z
TTL-compatible 5-bit DAC Core Output
Voltage
Applications
Power Supply for Pentium, Pentium ProTM,
z
Pentium II
Alpha
High-power 5V to 3.xV DC-DC Regulators
z
Low-voltage Distributed Power Supplies
z
Programmable Power Supplies
z
TM
TM
, Power PCTM, K6TM, 6×86TM, and
Microprocessors
RT9221
Package type
S : SOP-24
Operating temperature range
C: Commercial standard
Pin Configurations
Part Number Pin Configurations
RT9221CS
(Plastic SOP-24)
GND
GATE1
LDOS1
LDOS2
VCC
OVP
PGOOD
CSN
CSP
PGNDH
DH BSTL
PGNDL
TOP VIEW
1
2
3
4
5
6
7
8
9
10
11
12 13
24
23
22
21
20
19
18
17
16
15
14
GATE2
LDOV
VID0
VID1
VID2
VID3
VID4
VSEN
SHDN
BSTH
DL
DS9222-05 May 2001 www.richtek-ic.com.tw
1
RT9221
Absolute Maximum Ratings
z VCC to GND -0.3 to +5.5V
z PGND to GND ± 0.3V
z BSTH and BSTL to GND -0.3 to +14V
z Ambient Temperature Range 0 to +70°C
z Junction Temperature Range 0 to +125°C
z Storage Temperature Range -65 to +150°C
z Lead Temperature (Soldering, 10 sec.) 300°C
z Package Thermal Resistance
SOP-24, θ
JA
Electrical Characteristics
75°C/W
(VCC = 5V; GND = 0V; PGNDH = PGNDL = 0V; VSEN = VOUT; 0mV < (V
CSP-VCSN
) < 60mV; T
= 25°C)
A
Parameter Symbol Test Conditions Min Typ Max Units
Switching Section
Output Voltage
Supply Voltage
Supply Current
Load Regulation
Line Regulation
V
OUT
V
CC
I
CC
∆V
LOADIO
∆V
LINE
IO = 2A
VCC 4.5 -- 5.5 V
= 0.8A to 15A
VCC = 4.75V to 5.25V -- 0.5 -- %
-- (1) -- --
-- 3 6 mA
-- 1 -- %
Power On Reset Trip Point VCC Rising -- 4.2 --
Current Limit Voltage
V
LIMIT
V
CSP
- V
CSN
65 75 85
Oscillator Frequency 170 200 230
Oscillator Max Duty Cycle
DH Source
DH Sink
DL Source
DL Sink
D
MAX
V
V
V
V
BSTH
- V
DH
BSTH
- V
DL
- V
DH
PGNDH
- V
DL
PGNDL
= 1V
= 1V
= 3V
= 1V
90 95 --
-- 3.5 --
-- 3.5 --
-- 2 --
-- 2 --
OVP Threshold Voltage 114 120 122
V
mV
KHz
%
Ω
Ω
Ω
Ω
%
OVP Source Current
I
OVP
V
OVP
= 3.0V
Power Good Threshold Voltage VSEN Rising 87 -- 113
10 -- --
mA
%
Linear Sections
Quiescent Current
I
Q
Output Voltage (LDO1 RT9221) 2.450 2.500 2.550
Output Voltage (LDO2 RT9221) 1.470 1.500 1.530
Gain (AOL)
Load Regulation
Line Regulation
∆V
LOADIO
∆V
LINE
LDOV = 12V ----5
LDOS (1,2) to GATE (1,2) -- 65 --
= 0 to 5A
-- 1 --
LDOV = 11.4V to 12.6V -- 1 --
mA
V
V
dB
%
%
Note: (1) See output voltage table.
www.richtek-ic.com.tw DS9222-05 May 2001
2
Function Block Diagram
1. 25 V REF
VID4
VID3
VID2
VID1
VID0
DAC
VCC
CSN
CSP
+
_
70mV
OSCILLATOR
CURRENT LIMI T
R
Q
S
SHDN
LEVEL SHIFT
AND DRI VER
RT9221
BSTH
DH
PGNDH
VSEN
PGOOD
OVP
LDOS 1
GATE1
OPEN
DRAIN
_
_
VCC
LINEAR
CONTROLLER
2. 5V
SHOOT-
200KHz
REF
_
+
CONTROLLER
LINEAR
1. 5V
+
+
+
_
+
_
ERRO R AM P
GND
1. 26 5V
LDOV
THROUGH
CONTROL
DRIVER
LDOS 2GATE2
BSTL
DL
PGNDL
GND
DS9222-05 May 2001 www.richtek-ic.com.tw
3
Loading...