RT9223
5-Bit Programmable Synchronous PWM
Buck Converter Controller
General Description
The RT9223 is a high efficiency synchronous
switching regulator for modern CPU application. The
output is controlled by a 5-bit DAC programmed from
1.3V to 2.05V in 0.05V steps and from 2.1V to 3.5V
in 0.1V increments.
The switching controller drivers two N-MOSFETs at
200KHz frequency and provides an optimal solution
for size, efficiency and cost in any application
circuits. The controller also offers integrated
functions including PGOOD, output enable, over-
voltage, internal digital-count soft start, and current-
limiting protection in one chip.
Ordering Information
RT9223
Package type
S : SOP-20
Operating temperature range
C: Commercial standard
Features
z
High Efficiency Synchronous N-MOSFET
Driver Operating at 200KHz
z
1.3V ~ 2.05V (0.05V steps) and 2.1V ~ 3.5V
(0.1V steps) Output Voltage
z
Enable Input, PGOOD Output, OVP, and
Current-limiting Protection
z
Internal Digital-count Soft Start
Applications
Power Supply for Pentium ProTM, PowerPCTM,
z
TM
K6
, 6x86TM, and AlphaTM Microprocessors
High-power 5V to 3.xV DC-DC Regulators
z
Low-voltage Distributed Power Supplies
z
Programmable Step-down Power Supplies
z
Pin Configurations
Part Number Pin Configurations
DH
NC
TOP VIEW
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VID0
VID1
VID2
VID3
VID4
VSEN
SHDN
BSTH
BSTL
DL
RT9223CS
(Plastic SOP-20)
GND
VCC
OVP
PGOOD
CSN
CSP
PGNDH
PGNDL
DS9223-07 May 2001 www.richtek-ic.com.tw
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RT9223
Absolute Maximum Ratings
VCC to GND -0.3 to +5.5V
z
PGND to GND ± 0.3V
z
BST to GND -0.3 to +14V
z
Ambient Temperature Range 0 to +70°C
z
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-20, θ
JA
Electrical Characteristics
87°C/W
(VCC = 5V; GND = 0V; PGNDH = PGNDL = 0V; VSEN = VOUT; 0mV < (V
CSP-VCSN
) < 60mV; TA = 25°C)
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 4.3 -- 5.5 V
= 0.8A to 15A
VCC = 4.75V to 5.25V -- 0.5 -- %
-- (1) -- --
-- 2 5 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
BSTH
V
DH
V
BL
V
DL
- V
- V
– V
- V
DH
PGNDH
= 5V
DL
PGNDL
= 1V
= 1V
= 1V
90 95 --
-- 4.5 --
-- 3.5 --
-- 1 --
-- 2 --
OVP Threshold Voltage 114 120 122
V
mV
KHz
%
Ω
Ω
A
Ω
%
OVP Source Current
I
OVP
V
OVP
= 3.0V
Power Good Threshold Voltage VSEN Rising 87 -- 115
10 -- --
mA
%
Note: (1) See output voltage table.
www.richtek-ic.com.tw DS9223-07 May 2001
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Function Block Diagram
VCC
1. 25 V REF
VID4
VID3
VID2
VID1
VID0
DAC
CSN
CSP
_
+
70mV
OSCILLATOR
CURRENT LI MI T
R
Q
S
SHDN
LEVEL SHIFT
AND DRI VER
RT9223
BSTH
DH
PGNDH
VSEN
PGOOD
OVP
OPEN
DRAIN
VCC
SHOOT-
200KHz
+
_
+
_
+
_
+
_
ERRO R AMP
GND
_
+
THROUGH
CONTROL
DRIVER
BSTL
DL
PGNDL
DS9223-07 May 2001 www.richtek-ic.com.tw
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RT9223
Pin Description
Pin No. Pin Name Pin Function
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
GND Small signal analog and digital ground
VCC Power supply input
OVP
PGOOD
High signal out if V
(1)
Open collector logic output; High if VO within 10% of the setting point
CSN Current sense input (Negative)
CSP Current sense input (Positive)
PGNDH High side drive GIND
DH High side driver output
NC No connection
PGNDL Low side drive GND
DL Low side driver output
BSTL Supply for low side driver
BSTH Supply for high side driver
SHDN
(1)
Logic low shutdown the converter
VSEN Top end of internal feedback chain
VID4
VID3
VID2
VID1
VID0
(1)
(1)
(1)
(1)
(1)
Programming input (MSB)
Programming input
Programming input
Programming input
Programming input (LSB)
> setting point +20%
O
Note: (1) All logic level inputs and outputs are TTL compatible.
www.richtek-ic.com.tw DS9223-07 May 2001
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Table 1 Output Voltage Program
RT9223
Test Conditions
Output Voltage IO = 2A in application circuit
VID
43210
01111 1.287 1.300 1.313
01110 1.336 1.350 1.364
01101 1.386 1.400 1.414
01100 1.435 1.450 1.465
01011 1.485 1.500 1.515
01010 1.534 1.550 1.566
01001 1.584 1.600 1.616
01000 1.633 1.650 1.667
00111 1.683 1.700 1.717
00110 1.732 1.750 1.768
00101 1.782 1.800 1.818
00100 1.831 1.850 1.869
00011 1.881 1.900 1.919
00010 1.930 1.950 1.970
00001 1.980 2.000 2.020
Min Typ Max
Units
V
00000 2.029 2.050 2.071
11111 1.980 2.000 2.020
11110 2.079 2.100 2.121
11101 2.178 2.200 2.222
11100 2.277 2.300 2.323
11011 2.376 2.400 2.424
11010 2.475 2.500 2.525
11001 2.574 2.600 2.626
11000 2.673 2.700 2.727
10111 2.772 2.800 2.828
10110 2.871 2.900 2.929
10101 2.970 3.000 3.030
10100 3.069 3.100 3.131
10011 3.168 3.200 3.232
10010 3.267 3.300 3.333
10001 3.366 3.400 3.434
10000 3.465 3.500 3.535
DS9223-07 May 2001 www.richtek-ic.com.tw
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RT9223
Typical Application Circuit
5V I N
12V IN
OVP
VID0
VID1
VID2
VID3
VID4
SHDN
PGOOD
C1
0.1µF
R6
10
C2
1000µFx3
+
C7
1µF
R2
10K
C6
0.1µF
R5
10
2
3
20
19
18
17
14
1
10
VCC
OVP
VID0
VID1
VID2
VID3
SHDN
GND
PGNDL
NC
RT9223
CSP
CSN
VSEN
PGOOD
VID4
BSTH
DH
PGNDH
DL
BSTL
R3
L1
4µH
5mΩ
C3
1000µFx6
C4
0.1µF
VOUT
+
Q1
Q2
1N5817
R3
2.32kR41.00k
6
5
15
4
16
13
8
7
11
12
C5
0.1µF
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Package Information
RT9223
H
M
B
A
C
FD
Dimensions In Millimeters Dimensions In Inches
Symbol
Min Max Min Max
A 12.598 13.005 0.496 0.512
B 7.391 7.595 0.291 0.299
C 2.362 2.642 0.093 0.104
D 0.330 0.508 0.013 0.020
I
B
J
F 1.194 1.346 0.047 0.053
H 0.229 0.330 0.009 0.013
I 0.102 0.305 0.004 0.012
J 10.008 10.643 0.394 0.419
M 0.381 1.270
0.015 0.050
DS9223-07 May 2001 www.richtek-ic.com.tw
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RT9223
RICHTEK TECHNOLOGY CORP.
Headquarter
6F, No. 35, Hsintai Road, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5510047 Fax: (8863)5537749
www.richtek-ic.com.tw DS9223-07 May 2001
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek-ic.com.tw
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