RICHTEK RT9173-ACM5, RT9173-ACS Datasheet

RT9173/A

DS9173/A-06 March 2002 www.richtek-ic.com.tw

1

1.5A/3A Bus Termination Regulator

General Description

The RT9173/A regulator is designed to convert

voltage supplies ranging from 1.8V to 6V into a

desired output voltage which adjusted by two external

resistors, voltage divider. The regulator is capable of

sourcing or sinking up to 1.5A/3A of current while

regulating an output voltage to within 2% or less.

The RT9173/A, used in conjunction with series

termination resistors, provides an excellent voltage

source for active termination schemes of high speed

transmission lines as those seen in high speed

memory buses and distributed backplane designs.

The voltage output of the regulator can be used as a

termination voltage for DDR SDRAM.

Current limits in both sourcing and sinking mode, plus

on-chip thermal shutdown make the circuit tolerant of

the output fault conditions.

Applications

z

Computers

z

Disk Drives

z

CD-ROM

z

Supply Splitter

z

Graph Card

Ordering Information

RT9173/A



Features

z

Support Both DDR 1 (1.25VTT) and DDR 2

(0.9VTT) Requirements

z

Power TO-263-5 and SOP-8 Packages

z

Capable of Sourcing and Sinking Current

1.5A/3A

z

Current-limiting Protection

z

Thermal Protection

z

Integrated Power MOSFETs

z

Generates Termination Voltages for SSTL-2

z

High Accuracy Output Voltage at Full-load

z

Adjustable VOUT by External Resistors

z

Minimum External Components

z

Shutdown for Standby or Suspend Mode

Operation with High-impedance Output

Pin Configurations

Part Number Pin Configurations

RT9173ACM5

(Plastic TO-263-5)

TOP VIEW

1. VIN

2. GND

3. VCNTL (TAB)

4. REFEN

5. VOUT

RT9173CS

(Plastic SOP-8)

TOP VIEW

Function Block Diagram

Operating temperature range
C: Commercial standard

Package type
M5 : TO-263-5
S : SOP-8

3A sink & source

1.5A sink & source

Thermal

Current

Limit ing S en sor

VOUT

REFE N

GND

CNTL

VINVCNTL

12 34 5

VIN

GND

REFE N

VOUT

1

2

3

4

8

7

6

5

VCNTL

VCNTL

VCNTL

VCNTL

RT9173/A

www.richtek-ic.com.tw DS9173/A-06 March 2002

2

Pin Description

Pin Name Pin Function

VIN Power Input

GND Ground

VCNTL Gate Drive Voltage

REFEN Reference Voltage Input and Chip Enable

VOUT Output Voltage

Absolute Maximum Ratings

z

Input Voltage 7V

z

Power Dissipation Internally Limited

z

ESD Rating 2KV

z

Storage Temperature Range -65°C to 150°C

z

Lead Temperature (Soldering, 5 sec.) 260°C

z

Package Thermal Resistance

TO-263,θ

JC

7.7°C/W

TO-263,θ

JA

19.4°C/W

SOP-8, θ

JC

15.7°C/W

SOP-8, θ

JA

Note

45°C/W

Note: θ

JA

is measured with the component mounted on an evaluation PC board in free air that the required area of

copper is 300mm

2

or larger.

Electrical Characteristics

(Limits in standard typeface are for TA = 25°C, unless otherwise specified:

V

IN

= 2.5V, V

CNTL

= 3.3V, V

REFEN

= 1.25V, C

OUT

= 10µF (Ceramic))

Parameter Symbol Test Conditions Min Typ Max Units

Output Offset Voltage V

OS

Fig.1 -20 0 20 mV

IL : 0 → 1.5A, Fig.1 -- 0.8 2

Load Regulation ∆V

LOAD

IL : 0A → -1.5A -- 0.8 2

%

V

IN

1.8 2.5 --

Input Voltage Range

(DDR 1)

V

CNTL

Keep V

CNTL

≥ VIN on operation

power on and power off sequences

-- 3.3 6

V

Current In Shutdown Mode I

SHDN

V

REFEN

< 0.2V, RL = 180Ω, Fig.2 -- 50 90 µA

Short Circuit Protection

RT9173 Fig.3,4 2.1 -- --

Current limit

RT9173A

I

LIMIT

Fig.3,4 3.0 -- --

A

Over Temperature Protection

Thermal Shutdown Temperature T

SD

3.3V ≤ V

CNTL

≤ 5V 125 150 -- °C

Thermal Shutdown Hysteresis Guaranteed by design -- 50 -- °C

Shutdown Function

Output = High, Fig.5 0.8 -- --

Shutdown Threshold Trigger

Output = Low, Fig.5 -- -- 0.2

V

RT9173/A

DS9173/A-06 March 2002 www.richtek-ic.com.tw

3

Typical Application Circuit

Test Circuit

Fig.1 Output Voltage Tolerance, ∆V

OUT

Fig.2 Current in Shutdown Mode, I

SHCLN

R1 = R

2

= 100KΩ, RTT = 50Ω / 33Ω / 25Ω

C

OUT,min

= 10µF (Ceramic) + 1000µF under the worst case testing condition

R

DUMMY

= 1kΩ as for VOUT discharge when VIN is not present but VCNTL is present

C

SS

= 1µF, CIN = 470µF (Low ESR), C

CNTL

= 47µF

VIN VCNTL

REFEN VOUT

GND

R

TT

V

CNTL

= 3.3V

V

IN

= 2.5V

EN

R

2

C

SS

R

1

C

IN

C

OUT

C

CNTL

RT9173/A

R

DUMMY

2N70 02

VIN VCNTL

REFE N

RT9173/A

VOUT

GND

1. 25 V

2. 5V 3. 3V

V

OU T

C

OUT

I

L

V

VIN VCNTL

REFE N

RT9173/A

VOUT

GND

1.25V

2.5V

3.3V

V

OU T

C

OUT

V

R

L

A

0.2V

0V

1.25V

RL and C

OUT

Time d elay