Datasheet rt9228 Datasheets

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
±1% tolerance. The linear regulator uses an internal
drive device to provide 2.5V ±2.5% output voltage.
The linear controller drives an external N-channel
MOSFET or a low cost NPN bipolar transistor to
provide 1.5V ±2.5%.

Features

z 3-in-one Regulated Voltages for Microprocessor

Core, Clock, and GTL

z Compatible with HIP6018B
z Power-good Output Voltage Monitor

Switching section

z 5-bit DAC Programmable from 1.3V to 3.5V
z ±1% DAC Accuracy
z Fast Transient Response
z Full 0% to 100% Duty Cycle Driver
z Fixed 200kHz Switching Frequency
z Adaptive Non-overlapping Gate Driver
z Over-current Monitor Uses MOSFET R
z Over-voltage Protection Uses Lower MOSFET

Linear Section

z User-adjustable Linear Regulator Output Voltage
z MOSFET or NPN Driving Capability
z Ultra Fast Response Speed
z Under-voltage Protection
z Internal Thermal Shutdown

DS(ON)

The RT9228 monitors all the output voltages. A
Power-good signal is issued when the core voltage is
within ±10% of the DAC setting and the other levels
are above their under-voltage levels. Additional build­in 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’s R

DS(ON)

, which

eliminates the need for a current sensing resistor .

Ordering Information

RT9228 

Package type
S : SOP-24

Operating temperature range

C: Commercial standard

Applications

z Full Motherboard Power Regulation for Computer
z Low-voltage Distribution Power Supplies

Pin Configurations

Part Number Pin Configurations

RT9228CS
(Plastic SOP-24)

VCC
VID4
VID3
VID2

VID1
VID0

PGOOD

FAULT

SS
NC

FB2 GND

VIN2

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

UGATE1
PHASE1

LGATE1
PGND

OCSET1
VSEN1
FB1
NC
FB3

GATE3

VOT2

DS9228-03 July 2001 www.richtek.com

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RT9228

Absolute Maximum Ratings

z Supply Voltage +15V
z PGOOD, FAULT and GATE Voltage GND−0.3V to V
z Input, Output or I/O Voltage GND−0.3V to 7V
z Ambient Temperature Range 0°C to +70°C
z Junction Temperature Range 0°C to +125°C
z Storage Temperature Range −65°C to +150°C
z Lead Temperature (Soldering, 10 sec.) 300°C
z Package Thermal Resistance

SOP-24, θ

JA

75°C/W

Recommended Operating Conditions

z Supply Voltage +12V±10%
z Ambient Temperature Range 0°C to 70°C
z Junction Temperature Range 0°C to 125°C

CAUTION:

Stresses beyond the ratings specified in “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress only rating and operation of the device at these or any other conditions above those
indicated in the operational sections of this specification is not implied.

CC

+0.3V

Electrical Characteristics

(V

= 12V, PGND = 0V, TA = 25°C, unless otherwise specified)

CC

Parameter Symbol Test Conditions Min Typ Max Units

VCC Supply Current

Nominal Supply Current

I

CC

Power-On Reset

VCC Rising Threshold
VCC Falling Threshold
Rising VIN2 Under-voltage Threshold -- 2.8 -- V
VIN2 Under-voltage Hysteresis -- 0.5 -­Rising V

OCSET1

Threshold

Oscillator

Free Running Frequency 180 200 225
Ramp Amplitude

∆V

OSC

UGATE1, GATE3, LGATE1,
and VOUT2 Open

V

OCSET1

V

OCSET1

= 4.5V
= 4.5V

-- 10 -- mA

7.5 -- 9.5 V
7 -- 9 V

-- 1.25 --

-- 1.9 --

To be continued

V
V

kHz
V

P-P

www.richtek.com DS9228-03 July 2001

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Parameter Symbol Test Conditions Min Typ Max Units

Reference and DAC

RT9228

DAC (VID0-VID4) Input Low Voltage -- -- 0.8
DAC (VID0-VID4) Input High Voltage 2.0 -- -­DACOUT Voltage Accuracy DACOUT = 2.05 ~ 3.50V -1 -- 1
DACOUT Voltage Accuracy DACOUT = 1.30 ~ 2.00V -1% -- 20mV
Reference Voltage (Pin FB2 and FB3)

V

REF

1.240 1.265 1.290

Linear Regulator

Regulation

10mA < I

VOUT2

< 150mA

-2.5 -- 2.5
Under-voltage Level FB2 Rising -- 75 87
Under-voltage Hysteresis -- 100 -­Over-current Protection

I

OVP

180 230 --

Over-current Protection During Start-up -- 700 --

Linear Controller

Regulation

VSEN3 = GATE3
0 < I

GATE3

< 20mA

-2.5 -- 2.5
Under-voltage Level FB3 Rising -- 75 87

Under-voltage Hysteresis -- 100 -­Output Drive Current

VIN2 – VOUT3 > 1.5V

20 40 --

V
V

%

-

V

%

%
mV
mA
mA

%

%
mV
mA

PWM Controller Error Amplifier

DC Gain -- 65 --

PWM Controller Gate Driver

UGATE Source
UGATE Sink
LGATE Source
LGATE Sink

R

UGATE1

R

UGATE1VUGATE1

I

LGATE1

R

LGATE1VLGATE1

VCC = 12V
VCC - V

UGATE1

= 1V

VCC = 12V
V

LGATE1

= 2V
= 1V

= 1V

-- 3 7

-- 3 7

-- 1 --

-- 2 6

Protection

V

Over-voltage Trip

OUT1

FAULT Souring Current
OCSET1 Current Source
Soft-start Current

I

OVP

I

OCSET

I

SS

VSEN1 Rising 112 115 120
V
V

FAULT
OCSET1

= 8V

VSS = 1V

= 4.5V

10 14 --

170 200 230

-- 11 --

Power Good

V

Upper Threshold

OUT1

V

Under Voltage

OUT1

V

Hysteresis (VSEN1/DACOUT)

OUT1

PGOOD Voltage Low

VSEN1 Rising 108 -- 112
VSEN1 Rising 89 -- 95
Upper/Lower Threshold -- 2 -­I

PGOOD

= -4mA

-- -- 0.5

dB

Ω

Ω

A

Ω

%
mA

µA
µA

%

%

%

V

DS9228-03 July 2001 www.richtek.com

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RT9228

Function Block Diagram

FB3

GATE3

VIN2

VOUT2

FB2

FAULT

3.3V

0.25A

+

_

_

_

11µA

OCSET1VSEN1

+

_

+

_

+

_

OC1

+

_

OSCILLATOR

200µA

+

_

INHIBIT

PWM

PWM C O MP

LIN EAR
UNDER

VOLTAGE

0.3V

+

1.26V

+

VCC

5V

+

_

+

_

OC2

SOFT-START

& FAU LT

LOGIC

DACOUT

TTL D/A

CONVERTER

(DAC)

110%

90%

115%

LUV

0V

+

_

ERROR

AMP

COMPENSATION

VCC

POWER-ON

RESET (POR )

UPPER

DRIVE

GATE

CONTROL

LOGIC

LOWER

DRIVE

3.3V

PGOOD

VCC

UGATE1

PHASE1

VCC

LGATE1

PGND
GND

VID2

SS

VID0

VID1

VID4

VID3

Functional Pin Description

VCC (Pin 1)

Provide a 12V bias supply for the IC to this pin. This
pin also provides the gate bias charge for all the
MOSFETs controlled by the IC.

VID0, VID1, VID2, VID3, VID4 (Pin 6, 5, 4, 3, and 2)

VID0~4 are the input pins to the 5-bit DAC. The
states of these five pins program the internal voltage
reference, DACOUT. The level of DACOUT sets the
core converter output voltage. It also sets the core
PGOOD and OVP thresholds. Table 1 specifies the
DACOUT voltage of 32 combinations of VID levels.

PGOOD (Pin 7)

PGOOD is an open collector output used to indicate
the status of the output voltage. This pin is pulled low
when the core output is not within ±10% of the

FB1

DACOUT reference voltage and the other outputs are
below their under-voltage thresholds.

The PGOOD output is open for ‘11111’ VID codes
that inhibit operation. See table 1.

FAULT (Pin 8)

This pin is low during normal operation, but it is
pulled to about 8V (V

= 12V) in the event of an

CC

over-voltage or over-current condition.

SS (Pin 9)

Connect a capacitor from this pin to ground. This
capacitor, along with an internal 11µA (V

SS

>1V)
current source, sets the soft-start interval of the
converter.

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RT9228

FB2 (Pin 11)

Connect this pin to a resistor divider to set the linear
regulator output voltage. VIN2 (Pin 12) this pin
supplies power to the internal regulator. Connect this
pin to a suitable 3.3V source.

Additionally, this pin is used to monitor the 3.3V
supply. If, following a startup cycle, the voltage drops
below 2.8V (typically), the chip shuts down. A new
soft-start cycle is initiated upon return of the 3.3V
supply above the under-voltage threshold.

VOUT2 (Pin 13)

Output of the linear regulator. Supplies current up to
230mA.

GND (Pin 14)

Signal ground for the IC. All voltage levels are
measured with respect to this pin.

GATE3 (Pin 15)

Connect this pin to drive gate of an external
MOSFET or NPN. This pin provides the drive for the
linear controller’s pass transistor.

converter over-current (OC) trip point according to
the following equation:

I

I

PEAK

OCSET1×ROCSET1

=

R

DS (ON)

An over-current trip cycles the soft-sta rt function.
Sustaining an over-current for 2 soft-start intervals

shuts down the controller.

PGND (Pin 21)

This is the power ground of UGATE1 and LGATE1.
Tie the PWM converter’s lower MOSFET source to
this pin.

LGATE1 (Pin 22)

Connect LGATE1 to the PWM converter’s lower
MOSFET gate. This pin provides the gate drive for
the lower MOSFET.

PHASE1 (Pin 23)

Connect the PHASE1 pin to the PWM converter’s
upper MOSFET source. This pin is used to monitor
the voltage drop across the upper MOSFET for over­current protection.

FB3 (Pin 16)

Connect this pin to a resistor divider to set the linear
controller output voltage.

FB1 (Pin 18)

The FB1 pin is the inverting input of the error
amplifier.

VSEN1 (Pin 19)

This pin is connected to the PWM converter’s output
voltage. The PGOOD and OVP comparator circuits
use this signal to report output voltage status and for
over voltage protection.

OCSET1 (Pin 20)

Connect a resistor (R

OCSET1

drain of the upper MOSFET. R
200µA current source (I
MOSFET on-resistance (R

) from this pin to the

, an internal

OCSET

OCSET1

DS(ON)

), and the upper

) set the PWM

UGATE1 (Pin 24)

Connect UGATE1 pin to the PWM converter’s upper
MOSFET gate. This pin provides the gate drive for
the upper MOSFET.

DS9228-03 July 2001 www.richtek.com

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RT9228

Table 1. VOUT1 Voltage Program

Pin Name

VID4 VID3 VID2 VID1 VID0

0 1 1 1 1 1.30
0 1 1 1 0 1.35
0 1 1 0 1 1.40
0 1 1 0 0 1.45
0 1 0 1 1 1.50
0 1 0 1 0 1.55
0 1 0 0 1 1.60
0 1 0 0 0 1.65
0 0 1 1 1 1.70
0 0 1 1 0 1.75
0 0 1 0 1 1.80
0 0 1 0 0 1.85
0 0 0 1 1 1.90
0 0 0 1 0 1.95
0 0 0 0 1 2.00
0 0 0 0 0 2.05

Normal OUT1 Voltage

DACOUT

1 1 1 1 1 INHIBIT
1 1 1 1 0 2.10
1 1 1 0 1 2.20
1 1 1 0 0 2.30
1 1 0 1 1 2.40
1 1 0 1 0 2.50
1 1 0 0 1 2.60
1 1 0 0 0 2.70
1 0 1 1 1 2.80
1 0 1 1 0 2.90
1 0 1 0 1 3.00
1 0 1 0 0 3.10
1 0 0 1 1 3.30
1 0 0 1 0 3.30
1 0 0 0 1 3.40
1 0 0 0 0 3.50

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Typical Application Circuit

12V

L1

1µH

4x1000µF

R6
187

R8
1K

C1-4

+

C8
1000µF

R7
1K

12

15

16

13

11

R9
1K

5
4
3

2

6

+

GATE3

FB3

FB2

VID0

5V

GND

3.3V

V

OUT3

1.5V

V

OUT2

2.5V

Q3

RFD3055

+

+

F1

15A

C9
1000µF

C10
270µF

C20
1µF

VIN2

RT9228

VOUT2

VID1
VID2
VID3
VID4

R1
10

1

VCC

OCSET1

OCSET1

PGOOD

UGATE1

PHASE1

LGATE1

GND

14

PGND

VSEN1

FB1

FAULT

SS

C5-6
2x1µF

20

7

24

23

22
21

19

18

8

9

C7

1000pF

R2

1.21k

C12

0.039µF

Q1
PHB83N03LT

PHB95N03LT
Q2

L2

3.5µH

R4

4.99K

R5
732K

POWERGOOD

R3
10K

C13-19

7x1000µF

C11

0.68µF

RT9228

V

OUT1

1. 3 t o 3.5V

+

DS9228-03 July 2001 www.richtek.com

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RT9228

Package Information

H

M

B

A

C

FD

Dimensions In Millimeters Dimensions In Inches

Symbol

Min Max Min Max

A 15.189 15.596 0.598 0.614
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

www.richtek.com DS9228-03 July 2001

0.015 0.050

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RT9228

DS9228-03 July 2001 www.richtek.com

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RT9228

RICHTEK TECHNOLOGY CORP.

Headquarter

5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: [phone] Fax: [phone]

www.richtek.com DS9228-03 July 2001

RICHTEK TECHNOLOGY CORP.

Taipei Office (Marketing)

8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: [phone] Fax: [phone]
Email: [e-mail]

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