RichTek RT9179 Technical data

Preliminary

RT9179

Adjustable,300mA LDO Regulator with Enable

General Description

The RT9179 is a high performance linear voltage regulator

with enable high function and adjustable output with a

1.175V reference voltage. It operates from an input of 3V

to 5.5V and provides output current up to 300mA with two

external resistors to set the output voltage ranges from

1.175V to 4.5V.

The RT9179 has superior regulation over variations in line

and load. Also it provides fast respond to step changes in

load. Other features include over-current and over-

temperature protection. The device has enable pin to reduce

power consumption in shutdown mode.

The devices is available in the popular

SOT-23-5 package.

Ordering Information

RT9179

Package Type
B : SOT-23-5

Operating Temperature Range
C : Commercial Standard
P : Pb Free with Commercial Standard

Features

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300mV Dropout @ 300mA

z

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μμ

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z 150

μA Low Ground Pin Current

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μμ

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z Excellent Line and Load Regulation

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μμ

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z <1

μA Standby Current in Shutdown Mode

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μμ

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z Guaranteed 300mA Output Current

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z Stable with 1

zz

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z Adjustable Output Voltage Ranges from 1.175V to

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μμ

μF Input a nd Output Ceramic Capacitor

μμ

4.5V

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z Over-Temperature/Over-Current Protection

zz

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z RoHS Compliant and 100% Lead (Pb)-Free

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Applications

z Battery-Powered Equipment

z Graphic Card

z Peripheral Cards

z PCMCIA Card

Marking Information

For marking information, contact our sales representative

directly or through a RichTek distributor located in your

area, otherwise visit our website for detail.

Note :

RichTek Pb-free products are :

Pin Configurations

−RoHS compliant and compatible with the current require-

ments of IPC/JEDEC J-STD-020.

(TOP VIEW)

−Suitable for use in SnPb or Pb-free soldering processes.

−100% matte tin (Sn) plating.

VIN

GND

1

2

354

VOUT

ADJEN

SOT-23-5

DS9179-05 March 2005 www.richtek.com

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RT9179

Typical Application Circuit

Preliminary

V

IN

Chip Enable

C

V

1uF

OUT

1

C

3

0.1uF

Note: The external feedback resistors are in hundreds of OHM to hundreds of KOHM ranges.

RT9179CB

GND

1+

VOUT

ADJ

1

R

2

R

VIN

EN

= 1.175 x ( ) Volts

Adjustable Operation

Functional Pin Description

Pin No. Pin Name Pin Function

1 VIN Power Input Voltage

2 GND Ground

3 EN Chip Enable (Active High)

Adjust Output Voltage. The output voltage is set by the internal feedback resistors when

4 ADJ

this pin grounded. If external feedback resistors are applied, the output voltage will be:

1

V

= 1.175 × (1 + ) Volts

OUT

R

2

R

V

OUT

R

1

C

2

R

1uF

2

5 VOUT Output Voltage

Function Block Diagram

EN

Shutdown

Logic Control

1.175V
V

REF

and

+

_

Error

Amplifier

Current-Limit

and

Thermal Protection

MOS

Driver

VIN

Thermal

SHDN

VOUT

ADJ

GND

DS9179-05 March 2005www.richtek.com

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Preliminary

RT9179

Absolute Maximum Ratings (Note 1)

z Supply Input Voltage -------------------------------------------------------------------------------------------------- 6V

z Power Dissipation, P

@ TA = 25°C

D

SOT-23-5 ---------------------------------------------------------------------------------------------------------------- 0.4W

z Package Thermal Resistance (Note 7)

SOT-23-5, θJA----------------------------------------------------------------------------------------------------------- 250°C/W

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

z Junction Temperature ------------------------------------------------------------------------------------------------- 150°C
z Storage Temperature Range ---------------------------------------------------------------------------------------- −65°C to 150°C

z ESD Susceptibility (Note 2)

HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV

MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V

Recommended Operating Conditions (Note 3)

z Supply Input Voltage -------------------------------------------------------------------------------------------------- 3V to 5.5V

z Shutdown Input Voltage ---------------------------------------------------------------------------------------------- 0V to 5.5V
z Junction Temperature Range ---------------------------------------------------------------------------------------- −40°Cto 125°C

Electrical Characteristics

(V

= V

IN

+ 0.7V, I

OUT

Parameter Symbol Test Conditions Min Typ Max Units

Reference Voltage Tolerance V

Adjust Pin Current I

Output Voltage Range V

Quiescent Current (Note 5) IQ Enabled, I

Standby Current (Note 6) I

Current Limit I

Dropout Voltage (Note 4) V

Line Regulation ΔV

Thermal Shutdown Temperature TSD -- 170 -- °C

Thermal Shutdown Hysteresis ΔTSD -- 40 -- °C

EN Threshold

EN Current IEN V

= 10μA, C

OUT

Logic-Low Voltage VIL V

Logic-High Voltage V

= C

IN

= 1μF (Ceramic), T

OUT

1.163 1.175 1.187 V

REF

-- -- 10 nA

ADJ

1.175 -- 4.5 V

OUT

VIN = 5.5V, Shutdown -- -- 1 μA

STBY

0.5 -- -- A

LIM

DROP

V

LINE

V

IH

= 25°C unless otherwise specified)

A

I

= 10mA -- 10 --

OUT

I

= 300mA -- 300 -

OUT

+ 0.7V < VIN < 5.5V -- 0.001 -- %/V

OUT

= 3.3V, Shutdown -- -- 0.4

IN

= 3.3V, Enable 2.0 -- --

IN

= 5.5V, Enable -- -- 10 nA

IN

= 0mA -- 150 -- μA

OUT

mV

V

DS9179-05 March 2005 www.richtek.com

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