RICHTEK RT9204CS Datasheet

Preliminary

RT9204

Dual Regulator - Standard Buck PWM DC-DC and Linear

Power Controller

General Description

The RT9204 is a dual power controllers designed for

high performance graphics cards and computer

applications. The IC integrates a standard buck

controller, a linear regulator driver and protection

functions into a small 8-pin package.

The RT9204 uses a internal compensated voltage

mode PWM control for simple application design. An

internal 0.8V reference allows the output voltage to

be precisely regulated to low voltage requirement. A

fixed 600kHz oscillator reduce the component size for

saving board area.

The RT9204 protects the converter and regulator by

monitoring the output under voltage.

Applications

Motherboard Power Regulation for Computers

z

Subsystems Power Supplies

z

Cable Modems, Set Top Box, and DSL Modems

z

DSP and Core Communications processor

z

Supplies

Memory Power Supplies

z

Personal Computer Peripherals

z

Industrial Power Supplies

z

5V-Input DC-DC Regulators

z

Low Voltage Distributed Power Supplies

z

Features

z

Operate from 5V

z

0.8V Internal Reference

z

Voltage Mode PWM Control

z

Fast Transient Response

z

Fixed 600kHz Oscillator Frequency

z

Full 0~100% Duty Cycle

z

Internal Soft Start

z

Internal PWM Loop Compensation

Pin Configurations

Part Number Pin Configurations

GND

VCC

DRV

FBL

TOP VIEW

1

2

3

4

RT9204CS

(Plastic SOP-8)

Ordering Information

RT9204 

Package type

S : SOP-8

Operating temperature range

C : Commercial standard

8

7

6

5

UGATE

BOO T

SD

FB

DS9204-00 February 2002 www.richtek-ic.com.tw

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RT9204

Typical Application Circuit

Preliminary

V

OU T2

1. 6V

220µF

AU X

3. 3V

C6

Q1

2D1802

+

R4

100

R5

100

R1

10

C5 1µF

1

GND

2

VCC

3

DRV

4

FBL

UGATE

RT9204

BOOT

SD

FB

R2

120

8

7

V

OU T1

2. 5V

6

5

R3

250

C7

10nF

Fig.1 RT9204 powered from 5V only

C3

0. 1µF

+

L1

5µH

C4 1000µF

MU

D1

C2 1µF

5V

+

C1 470µF

V

OU T2

1. 6V

220µF

V

3. 3V

AU X

C6

R1

10

C5 1µF

1

GND

2

VCC

Q1

R4

100

+

R5

100

3

4

C7 1µF

DRV

FBL

UGATE

RT9204

BOOT

SD

FB

R2

120

8

7

V

OU T1

2. 5V

6

5

R3

250

C3

10nF

5µH

+

C4 1000µF

L1

12V

MU

D1

C2 1µF

5V

+

C1 470µF

Fig.2 RT9204 powered from 12V

www.richtek-ic.com.tw DS9204-00 February 2002

2

C

VCC

1µF

GND

VCC

Layout Notes

1. Put C

& C2 to be near the MU drain and ML source nodes.

1

2. Put RT9204 to be near the C

3. Put C

4. Put C

BOOT

VCC

Function Block Diagram

Preliminary

+

C

OUT

1000µF

C

BOOT

RT9204

Layout Placement

as close as to BOOT pin

as close as to VCC pin

0.1µF

OUT

L

GS

5µH

Diod e

MU

D

C1 1µF

GND Re tur n

+

RT9204

C2 470µF

VCC

DRV

FBL

FB

GND

LDO

0.8V

Reference

0.8V

Error Amp

++

_

0.5V

+

35dB

Power

on Reset

6.0V

Regulator

BOOT

Soft Start

_

UVP

+

1V

_

OVP

+

_

UVP

+

_

SS

+

PWM

_

Control

Logic

UGATE

600kH z

Oscillator

DS9204-00 February 2002 www.richtek-ic.com.tw

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RT9204

Preliminary

Absolute Maximum Ratings

z

Supply Voltage VCC 7V

z

BOOT & UGATE to GND 15V

z

Input, Output or I/O Voltage GND−0.3V ~ 7V

z

Power Dissipation, PD @ TA = 25°C SOP-8 0.625W

z

Package Thermal Resistance SOP-8, θ

z

Ambient Temperature Range 0°C ~ +70°C

z

Junction Temperature Range -40°C ~ +125°C

z

Storage Temperature Range -65°C ~ +150°C

z

Lead Temperature (Soldering, 10 sec.) 260°C

JA

160°C/W

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

(V

= 5V, TA = 25°C, Unless otherwise specified.)

CC

Parameter Symbol Test Conditions Min Typ Max Units

VCC Supply Current

Nominal Supply Current

VCC Regulated Voltage

I

V

CC

UGATE, LGATE open -- 3 -- mA

BOOT=

V

12V -- 6 -- V

Power-On Reset

Rising VCC Threshold 3.75 4.1 4.35 V

VCC Threshold Hysteresis -- 0.5 -- V

Reference

Reference Voltage Both FB & FBL 0.784 0.8 0.816 V

Oscillator

Free Running Frequency 550 600 650 KHz

Ramp Amplitude

∆ V

OSC

-- 1.75 --

V

PWM Error Amplifier

DC Gain -- 35 -- dB

PWM Controller Gate Driver

Upper Drive Source

Upper Drive Sink

R

UGATEVBOOT

R

UGATEVUGATE

= 12V; V

= 1V

BOOT

- V

UGATE

= 1V

-- 7 --

-- 5 --

Linear Regulator

DRV Driver Source

V

DRV

= 2V

100 -- -- mA

Protection

FB Over-Voltage Trip FB Rising -- 1 -- V

FB & FBL Under-Voltage Trip FB & FBL Falling -- 0.5 -- V

Soft-Start Interval -- 1 -- mS

SD Pin Threshold VCC = 5V -- 1.5 -- V

SD pin Sink Current VCC = 5V -- 40 --

P-P

Ω

µA

www.richtek-ic.com.tw DS9204-00 February 2002

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Typical Operating Charateristics

Preliminary

RT9204

VCC = 5V V

= 2.2V

OUT

Power On

Time

Load Transient

UGATE

V

CC

OUT1

OUT2

V

CC

OUT1

OUT2

Power Off

Time

Load Transient

UGATE

VCC = 5V

V

OUT

= 2.2V

V

OUT

Time

Short Hiccup

V

= 5V

CC

V

OUT

C

OUT

VCC = 5V V

OUT

= 2.2V

= 3000µF

= 2.2V

UGATE

Reference (V)

0.803

0.802

0.801

0.800

0.799

0.798

0.797

V

OUT

= 5V

V

CC

V

OUT

C

OUT

Time

Reference vs. Temperature

= 2.2V

= 3000µF

0.796

Time

-50 0 50 100 150

Temperature ( C)

°

DS9204-00 February 2002 www.richtek-ic.com.tw

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