Preliminary

RT9227A

DS9227A-02 July 2001

www.richtek.com

Advanced PWM and Dual Fixed Linear Power Controller

General Description

The RT9227A 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 RT9227A 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 a fixed 2.5V

2.5% output

voltage. The linear controller drives an external N-
channel MOSFET or a low cost NPN bipolar
transistor to provide a fixed 1.5V

2.5%.

The RT9227A 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 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's R

DS(ON)

, which

eliminates the need for a current sensing resistor.

Ordering Information

RT9227A

Features

3-in-one Regulated Voltages for Microprocessor
Core, Clock, and GTL

Compatible with HIP6016

Power-good Output Voltage Monitor

Switching section

5-bit DAC Programmable from 1.3V to 3.5V

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

Fixed 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 Distributed Power Supplies

Pin Configurations

Part Number

Pin Configurations

RT9227ACS

(Plastic SOP-24)

TOP VIEW

Operating temperature range

C: Commercial standard

Package type
S : SOP-24

4
5

VID4
VID3
VID2
VID1
VID0

PGOOD

FAULT

SS
NC

UGATE1
PHASE1
LGATE1
PGND
OCSET1
VSEN1
FB1
NC
FB3
GATE3

VCC

VIN2

FB2

GND
VOT2

RT9227A

Preliminary

www.richtek.com

DS9227A-02 July 2001

Absolute Maximum Ratings

Supply Voltage

+15V

PGOOD and GATE Voltage

GND

0.3V to V

+0.3V

Input, Output or I/O Voltage

GND

0.3V to 7V

Ambient Temperature Range

C to +70

Junction Temperature Range

C to +125

Storage Temperature Range

-65

C to +150

Lead Temperature (Soldering, 10 sec.)

300

Package Thermal Resistance
SOP-24,

C/W

Recommended Operating Conditions

Supply Voltage

+12V

10%

Ambient Temperature Range

C to 70

Junction Temperature Range

C to 125

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.

Electrical Characteristics

(VCC = 12V, PGND = 0V, T

= 25

C, unless otherwise specified)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Units

VCC Supply Current

Nominal Supply Current

UGATE1, GATE3, LGATE1,
and VOUT2 Open

Power-On Reset

VCC Rising Threshold

OCSET1

= 4.5V

7.5

9.5

VCC Falling Threshold

OCSET1

= 4.5V

Rising VIN2 Under-Voltage Threshold

2.8

VIN2 Under-Voltage Hysteresis

0.5

Rising V

OCSET1

Threshold

1.25

Oscillator

Free Running Frequency

180

200

225

KHz

Ramp Amplitude

OSC

1.9

P-P

Reference and DAC

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

DACOUT Voltage Accuracy

DACOUT = 1.30 ~ 2.00V

-1%

20mV

To be continued

Preliminary

RT9227A

DS9227A-02 July 2001

www.richtek.com

Parameter

Symbol

Test Conditions

Min

Typ

Max

Units

Linear Regulator

Regulation Voltage

REG

10mA

VOUT2

150mA

2.437

2.500

2.563

Under-Voltage Level

FB2 Rising

1.875

2.175

Under-Voltage Hysteresis

100

Over-Current Protection

180

230

Over-Current Protection During Start-Up

700

Linear Controller

Regulation Voltage

REG

VSEN3 = GATE3
0

GATE3

20mA

1.462

1.500

1.538

Under-Voltage Level

FB3 Rising

1.125

1.305

Under-Voltage Hysteresis

100

PWM Controller Error Amplifier

DC Gain

PWM Controller Gate Driver

UGATE Source

UGATE1

VCC = 12V
VCC - V

UGATE1

= 1V

UGATE Sink

UGATE1

= 1V

LGATE Source

LGATE1

VCC = 12V, V

LGATE1

= 2V

LGATE Sink

LGATE1

= 1V

Protection

OUT1

Over-Voltage Trip

VSEN1 Rising

112

115

120

FAULT Souring Current

FAULT

= 8V

OCSET1 Current Source

OCSET

OCSET1

= 4.5V

170

200

230

Soft-Start Current

= 1V

Power Good

OUT1

Upper Threshold

VSEN1 Rising

108

112

OUT1

Under Voltage

VSEN1 Rising

OUT1

Hysteresis (VSEN1 / DACOUT)

Upper/Lower Threshold

PGOOD Voltage Low

PGOOD

= -4mA

0.5

RT9227A

Preliminary

www.richtek.com

DS9227A-02 July 2001

Function Block Diagram

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)
VIDO-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

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

over-voltage or over-current condition.

SS (Pin 9)
Connect a capacitor from this pin to ground. This
capacitor, along with an internal 11

A (V

>1V)

current source, sets the soft-start interval of the
converter.

110%

90%

115%

POWER-ON

RESET (POR)

SOFT-START

& FAULT

LOGIC

TTL D/A

CONVERTER

(DAC)

OSCILLATOR

GATE

CONTROL

LOGIC

LINEAR
UNDER

VOLTAGE

PGOOD

PHASE1

LGATE1

PGND
GND

VCC

VSEN3

FAULT

VID0

VID1

VID2

VID3

3.3V

OCSET1

VSEN1

COMPENSATION

GATE3

0.3V

3.3V

VIN2

1.26V

VOUT2

FB2

OC2

0.25A

VCC

VID4

DACOUT

ERROR

AMP

LUV

OC1

FB1

PWM

INHIBIT

PWM COMP

LOWER

DRIVE

VCC

UPPER

DRIVE

UGATE1

200

Preliminary

RT9227A

DS9227A-02 July 2001

www.richtek.com

FB2 (Pin 11)
Connect this pin to V

OUT2

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 2.55V (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 the gate of an external MOSFET
or the base of an NPN. This pin provides the drive for
the linear controller's pass transistor.

FB3 (Pin 16)
Connect this pin to V

OUT3

to set the linear controller

output voltage.

FB (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

) from this pin to the

drain of the upper MOSFET. R

OCSET1

, an internal

200

A current source (I

OCSET1

), and the upper

MOSFET on-resistance (R

DS(ON)

) set the PWM

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

OCSET1

PEAK

DS(ON)

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.

An over-current trip cycles the soft-start function.
Sustaining an over-current for 2 soft-start intervals
shuts down the controller.

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 over-
current protection.

UGATE1 (Pin 24)
Connect UGATE pin to the PWM converter's upper
MOSFET gate. This pin provides the gate drive for
the upper MOSFET.

RT9227A

Preliminary

www.richtek.com

DS9227A-02 July 2001

Table 1. VOUT1 Voltage Program

Pin Name

VID4

VID3

VID2

VID1

VID0

Normal OUT1 Voltage

DACOUT

1.30

1.35

1.40

1.45

1.50

1.55

1.60

1.65

1.70

1.75

1.80

1.85

1.90

1.95

2.00

2.05

INHIBIT

2.10

2.20

2.30

2.40

2.50

2.60

2.70

2.80

2.90

3.00

3.10

3.30

3.40

3.50

Preliminary

RT9227A

DS9227A-02 July 2001

www.richtek.com

Typical Application Circuit

3.5

1000pF

1.21k

FAULT

FB1

VSEN1

PGND

LGATE1

PHASE1

UGATE1

PGOOD

OCSET1

VCC

VIN2

GATE3

FB3

VOUT2

FB2

OCSET1

VID0

VID1
VID2
VID3
VID4 GND

5
4
3

POWERGOOD

C5-6
2x1

R1
10

C20
1

C1-4

4x1000

C8
1000

RFD3055

C9
1000

C10
270

OUT3

1.5V

OUT2

2.5V

3.3V

GND

12V

C12
0.039

R5
732K

C11

0.68

Q1
PHB83N03LT

PHB95N03LT
Q2

R4
4.99K

C13-19

7x1000

R3
10K

OUT1

1.3 to 3.5V

RT9227A

15A

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: RT9227A

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: RT9227A