RT9168-31CSH - Richtek Technology

RT9168/A

DS9168/A-03 May 2001 www.richtek-ic.com.tw

200mA/500mA Fixed Output Voltage LDO Regulator

General Description

The RT9168/A is a 200mA/500mA low dropout and

micropower regulator suitable for portable

applications. The output voltages range from 1.5V to

5.0V in 100mV increments and 2% accuracy. The

RT9168/A is designed for use with very low ESR

capacitors. The output remains stable even with a

1µF ceramic output capacitor.

The RT9168/A uses an internal PMOS as the pass

device, which does not cause extra GND current in

heavy load and dropout conditions. The shutdown

mode of nearly zero operation current makes the IC

suitable for battery-powered devices. Other features

include current limiting and over temperature

protection. The SOP-8 and SOT-25 packages are

also available for larger power dissipation and

design flexibility.

Applications

z Cellular Telephones

z Laptop, Notebook, and Palmtop Computers

z Battery-powered Equipment

z Hand-held Equipment

Ordering Information

RT9168/A-  

Features

z Stable with Low-ESR Output Capacitor

z Low Dropout Voltage (220mV at 200mA)

z Low Operation Current - 80µ

µµ

µA Typical

z Shutdown Function

z Low Temperature Coefficient

z Current and Thermal Limiting

z Custom Voltage Available

z SOT-25 and SOP-8 Packages

Pin Configurations

Part Number Pin Configurations

RT9168/A-CBR

(Plastic SOT-25)

TOP VIEW

1. OUT

2. GND

3. IN

4. SHDN

5. NC

RT9168/A-CS

RT9168/A-CSH

(Plastic SOP-8)

TOP VIEW

Typical Application Circuit

Package type

BR : SOT-25

S : SOP-8

SH : SOP-8, High shutdown

Operating temperature range

C: Commercial standard

Output voltage

15 : 1.5V

16 : 1.6V

49 : 4.9V

50 : 5.0V

500mA Output current

200mA Output current

321

OUT

GND

SHDN/SHDN

RT9168

GND

IN OUT VOU T

COUT

1µF

VIN

CIN

1µF

SHDN NC

SHDN

RT9168/A

www.richtek-ic.com.tw DS9168/A-03 May 2001

Marking Information

Part Number Marking

RT9168-15CBR L0

RT9168-16CBR L1

RT9168-17CBR L2

RT9168-18CBR L3

RT9168-19CBR L4

RT9168-20CBR L5

RT9168-21CBR L6

RT9168-22CBR L7

RT9168-23CBR L8

RT9168-24CBR L9

RT9168-25CBR LA

RT9168-26CBR LB

RT9168-27CBR LC

RT9168-28CBR LD

RT9168-29CBR LE

RT9168-30CBR LF

RT9168-31CBR LG

RT9168-32CBR LH

RT9168-33CBR LJ

RT9168-34CBR LK

RT9168-35CBR LL

RT9168-36CBR LM

RT9168-37CBR LN

RT9168-38CBR LP

RT9168-39CBR LQ

RT9168-40CBR LR

RT9168-41CBR LS

RT9168-42CBR LT

RT9168-43CBR LU

RT9168-44CBR LV

RT9168-45CBR LW

RT9168-46CBR LX

RT9168-47CBR LY

RT9168-48CBR LZ

RT9168-49CBR CL

RT9168-50CBR CM

Part Number Marking

RT9168A-15CBR M0

RT9168A-16CBR M1

RT9168A-17CBR M2

RT9168A-18CBR M3

RT9168A-19CBR M4

RT9168A-20CBR M5

RT9168A-21CBR M6

RT9168A-22CBR M7

RT9168A-23CBR M8

RT9168A-24CBR M9

RT9168A-25CBR MA

RT9168A-26CBR MB

RT9168A-27CBR MC

RT9168A-28CBR MD

RT9168A-29CBR ME

RT9168A-30CBR MF

RT9168A-31CBR MG

RT9168A-32CBR MH

RT9168A-33CBR MJ

RT9168A-34CBR MK

RT9168A-35CBR ML

RT9168A-36CBR MM

RT9168A-37CBR MN

RT9168A-38CBR MP

RT9168A-39CBR MQ

RT9168A-40CBR MR

RT9168A-41CBR MS

RT9168A-42CBR MT

RT9168A-43CBR MU

RT9168A-44CBR MV

RT9168A-45CBR MW

RT9168A-46CBR MX

RT9168A-47CBR MY

RT9168A-48CBR MZ

RT9168A-49CBR CN

RT9168A-50CBR CP

RT9168/A

DS9168/A-03 May 2001 www.richtek-ic.com.tw

Pin Description

Pin Name Pin Function

IN Input

GND Ground

SHDN (SHDN) Active Low (High) Shutdown Input

NC No Connection

OUT Output

Function Block Diagram

_MOS Driver

Current-Limit

and

Thermal

Protection

Shutdown

and

Logic Control

VREF

Error Amp

GND

OUT

SHDN

RT9168/A

www.richtek-ic.com.tw DS9168/A-03 May 2001

Absolute Maximum Ratings

z Input Voltage 8V

z Power Dissipation, PD @ TA = 25°C

SOT-25 0.25W

SOP-8 0.625W

z Operating Junction Temperature Range −40°C to 125°C

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

z Package Thermal Resistance

SOT-25, θJA 250°C/W

SOP-8, θJA 160°C/W

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

Electrical Characteristics

(VIN = 5.0V, CIN = 1µF, COUT = 1µF, TA = 25°C, unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Units

2.9 -- 7

Input Voltage Range VIN IL = 50mA 2.7 -- 7 V

Output Voltage Accuracy ∆VOUT IL = 1mA -2 -- +2 %

RT9168 200 -- -- mA

Maximum Output

Current RT9168A IMAX 500 -- -- mA

RT9168 -- 300 -- mA

Current Limit RT9168A ILIMIT RLOAD = 1 Ohm -- 700 -- mA

RT9168/A No Load -- 80 150

RT9168 IOUT = 200mA -- 90 150

GND Pin Current

RT9168A

IOUT = 500mA -- 90 150

µA

RT9168/A IOUT = 1mA -- 1.1 5 mV

RT9168/A IOUT = 50mA -- 55 100 mV

RT9168/A IOUT = 200mA -- 220 300 mV

Dropout Voltage (Note)

(VOUT(Nominal)≥3.0V

Version)

RT9168A

VDROP

IOUT = 500mA -- 600 750 mV

Line Regulation ∆VLINE VIN = (VOUT+0.15) to 7V, IOUT = 1mA -0.2 -- +0.2 %/V

IOUT = 0mA to 200mA -- 0.01 0.04

Load Regulation ∆VLOAD IOUT = 0mA to 500mA -- 0.01 0.04 %/mA

SHDN, SHDN Input High Threshold VIH VIN = 3V to 5.5V 2.2 -- -- V

SHDN, SHDN Input Low Threshold VIL VIN = 3V to 5.5V -- -- 0.4 V

SHDN, SHDN Bias Current ISD -- -- 100 nA

Shutdown Supply Current IGSD VOUT = 0V -- 0.01 1 µA

Thermal Shutdown Temperature TSD -- 155 -- °C

Ripple Rejection PSRR F = 100Hz, CBP = 10nF, COUT = 10µF-- 58 -- dB

Notes: Dropout voltage definition: VIN - VOUT when VOUT is 50 mV below the value of VOUT at VIN = VOUT + 0.5V

RT9168/A

DS9168/A-03 May 2001 www.richtek-ic.com.tw

Typical Operating Charateristics

GND Current vs. Temp.

105

120

-50 -25 0 25 50 75 100 125 150

Temperature ( )

GND Current ( A)

VOUT = 3.3V

°C )

Current Limit vs. Temp.

100

200

300

400

500

600

700

800

900

-50 -25 0 25 50 75 100 125 150

Current Limit (mA)

Temperature ( )

RT9168A

VOUT = 3.3V

°C )

Current Limit vs. Temp.

120

180

240

300

360

420

480

-50 -25 0 25 50 75 100 125 150

Current Limit (mA)

Temperature ( )

RT9168

VOUT = 3.3V

(°C )

PSRR

10 100 1000 10000 100000 10000

Frequency (KHz)

PSRR (dB)

ILOAD = 1mA, COUT = 4.7µF

VOUT = 3.3V

10 100 1K 10K 100K 1M

Output Voltage vs. Temp.

3.25

3.26

3.27

3.28

3.29

3.30

3.31

3.32

3.33

-50 -25 0 25 50 75 100 125 150

Output Voltage (V)

Temperature ( )

VOUT = 3.3V

°C )

Dropout Voltage vs. Output Current

100

150

200

250

300

0 25 50 75 100 125 150 175 200

Output Current (mA)

Dropout Voltage (V)

VOUT = 3.3V

85°C

25°C

-40°C

(mV)

RT9168/A

www.richtek-ic.com.tw DS9168/A-03 May 2001

≈

≈≈

≈

≈≈

≈

-50

-20

Load Transient Response

Time

(

S/Div

)

Load Current

(mA)

Output Voltage

Deviation (mV)

COUT = 4.7µF

CIN = 10µF

VOUT = 3.0V

VIN = 4V

2 >

2 >2 >

2 >

≈

≈≈

≈

≈≈

≈

-50

-20

Load Transient Response

Time

(

S/Div

)

Load Current

(mA)

Output Voltage

Deviation (mV)

COUT = 1µF

CIN = 10µF

VOUT = 3.0V

VIN = 4V

↓

≈

≈≈

≈

≈≈

≈

150

100

-50

Line Transient Response

Time (1mS/Div)

Input Voltage (V) Output Voltage (mV)

COUT = 1µF

VOUT = 3.0V

Loading = 1mA

↓

≈

≈≈

≈

≈≈

≈

150

100

-50

Line Transient Response

Time

(

500

S/Div

)

Input Voltage (V) Output Voltage (mV)

COUT = 4.7µF

VOUT = 3.0V

Loading = 1mA

↓

≈

≈≈

≈

≈≈

≈

150

100

-50

Line Transient Response

Time (1mS/Div)

Input Voltage (V) Output Voltage (mV)

COUT = 1µF

VOUT = 3.0V

Loading = 50mA

↓

≈

≈≈

≈

≈≈

≈

-20

Line Transient Response

Time

(

500

S/Div

)

Input Voltage (V) Output Voltage (mV)

COUT = 4.7µF

VOUT = 3.0V

Loading = 50mA

RT9168/A

DS9168/A-03 May 2001 www.richtek-ic.com.tw

Applications Guides

Capacitor Selection and Regulator Stability

Like any low-dropout regulator, the external capacitors

used with the RT9168/A must be carefully selected for

regulator stability and performance.

Using a capacitor whose value is > 1µF on the

RT9168/A input and the amount of capacitance can be

increased without limit. The input capacitor must be

located not more than 0.5" from the input pin of the IC

and returned to a clean analog ground. Any good

quality ceramic or tantalum can be used for this

capacitor. The capacitor with larger value and lower

ESR (equivalent series resistance) provides better

PSRR and line-transient response.

The output capacitor must meet both requirements for

minimum amount of capacitance and ESR in all LDO

applications. The RT9168/A is designed specifically to

work with low ESR ceramic output capacitor in space-

saving and performance consideration. Using a

ceramic capacitor whose value is at least 1µF with

ESR is > 5mΩ on the RT9168/A output ensures

stability. The RT9168/A still works well with output

capacitor of other types due to the wide stable ESR

range. Fig.1 shows the curves of allowable ESR range

as a function of load current for various output

voltages and capacitor values. Output capacitor of

larger capacitance can reduce noise and improve

load-transient response, stability, and PSRR. The

output capacitor should be located not more than

0.5" from the VOUT pin of the RT9168/A and returned

to a clean analog ground.

Note that some ceramic dielectrics exhibit large

capacitance and ESR variation with temperature. It

may be necessary to use 2.2µF or more to ensure

stability at temperatures below -10°C in this case. Also,

tantalum capacitors, 2.2µF or more may be needed to

maintain capacitance and ESR in the stable region for

strict application environment.

Tantalum capacitors maybe suffer failure due to surge

current when it is connected to a low-impedance

source of power (like a battery or very large capacitor).

If a tantalum capacitor is used at the input, it must be

guaranteed to have a surge current rating sufficient for

the application by the manufacture.

Load-Transient Considerations

The RT9168/A load-transient response graphs (see

Typical Operating Characteristics) show two

components of the output response: a DC shift from

the output impedance due to the load current

change, and the transient response. The DC shift is

quite small due to the excellent load regulation of the

IC. Typical output voltage transient spike for a step

change in the load current from 0mA to 50mA is tens

mV, depending on the ESR of the output capacitor.

Increasing the output capacitor’s value and

decreasing the ESR attenuates the overshoot.

Shutdown Input Operation

The RT9168/A is shutdown by pulling the SHDN

input low, and turned on by driving the input high. If

this feature is not to be used, the SHDN input should

be tied to VIN to keep the regulator on at all times

(the SHDN input must not be left floating).

Fig. 1

COUT = 4.7µF

COUT = 1µF

Ω

ion of Stable C

OUT

ESR vs. Load Current

0 40 80 120 160 200

Load Current (mA)

COUT ESR (Ω)

100

0.001

0.01

0.1

(mΩ)

RT9168/A

www.richtek-ic.com.tw DS9168/A-03 May 2001

To ensure proper operation, the signal source used to

drive the SHDN input must be able to swing above and

below the specified turn-on/turn-off voltage thresholds

which guarantee an ON or OFF state (see Electrical

Characteristics). The ON/OFF signal may come from

either CMOS output, or an open-collector output with

pull-up resistor to the RT9168/A input voltage or

another logic supply. The high-level voltage may

exceed the RT9168/A input voltage, but must remain

within the absolute maximum ratings for the SHDN pin.

Internal P-Channel Pass Transistor

The RT9168/A features a typical 1.1Ω P-channel

MOSFET pass transistor. It provides several

advantages over similar designs using PNP pass

transistors, including longer battery life. The P-channel

MOSFET requires no base drive, which reduces

quiescent current considerably. PNP-based regulators

waste considerable current in dropout when the pass

transistor saturates. They also use high base-drive

currents under large loads. The RT9168/A does not

suffer from these problems and consume only 80µA of

quiescent current whether in dropout, light-load, or

heavy-load applications.

Input-Output (Dropout) Voltage

A regulator’s minimum input-output voltage

differential (or dropout voltage) determines the

lowest usable supply voltage. In battery-powered

systems, this will determine the useful end-of-life

battery voltage. Because the RT9168/A uses a P-

channel MOSFET pass transistor, the dropout

voltage is a function of drain-to-source on-resistance

[RDS(ON)] multiplied by the load current.

Reverse Current Path

The power transistor used in the RT9168/A has an

inherent diode connected between the regulator

input and output (see Fig.2). If the output is forced

above the input by more than a diode-drop, this

diode will become forward biased and current will

flow from the VOUT terminal to VIN. This diode will

also be turned on by abruptly stepping the input

voltage to a value below the output voltage. To

prevent regulator mis-operation, a Schottky diode

should be used in any applications where

input/output voltage conditions can cause the

internal diode to be turned on (see Fig.3). As shown,

the Schottky diode is connected in parallel with the

internal parasitic diode and prevents it from being

turned on by limiting the voltage drop across it to

about 0.3V. < 100 mA to prevent damage to the part.

Current Limit and Thermal Protection

The RT9168 includes a current limit which monitors

and controls the pass transistor’s gate voltage limiting

the output current to 300mA Typ. (700mA Typ. for

RT9168A). Thermal-overload protection limits total

power dissipation in the RT9168/A. When the junction

temperature exceeds TJ = +155°C, the thermal sensor

signals the shutdown logic turning off the pass

transistor and allowing the IC to cool. The thermal

sensor will turn the pass transistor on again after the

IC’s junction temperature cools by 10°C, resulting in a

pulsed output during continuous thermal-overload

conditions. Thermal-overloaded protection is designed

to protect the RT9168/A in the event of fault conditions.

Do not exceed the absolute maximum junction-

temperature rating of TJ = +150°C for continuous

operation. The output can be shorted to ground for an

Fig. 2

VIN VOU T

Fig. 3

VIN VOU T

RT9168/A

DS9168/A-03 May 2001 www.richtek-ic.com.tw

indefinite amount of time without damaging the part by

cooperation of current limit and thermal protection.

Operating Region and Power Dissipation

The maximum power dissipation of RT9168/A depends

on the thermal resistance of the case and circuit board,

the temperature difference between the die junction

and ambient air, and the rate of airflow. The power

dissipation across the device is P = IOUT (VIN - VOUT).

The maximum power dissipation is: PMAX = (TJ - TA)

/θJA

where TJ - TA is the temperature difference between

the RT9168/A die junction and the surrounding

environment, θJA is the thermal resistance from the

junction to the surrounding environment. The GND pin

of the RT9168/A performs the dual function of

providing an electrical connection to ground and

channeling heat away. Connect the GND pin to ground

using a large pad or ground plane.

RT9168/A

www.richtek-ic.com.tw DS9168/A-03 May 2001

Package Information

Dimensions In Millimeters Dimensions In Inches

Symbol Min Max Min Max

A 0.889 1.295 0.035 0.051

A1 0.000 0.152 0.000 0.006

B 1.397 1.803 0.055 0.071

b 0.356 0.559 0.014 0.022

C 2.591 2.997 0.102 0.118

D 2.692 3.099 0.106 0.122

e 0.838 1.041 0.033 0.041

H 0.102 0.254 0.004 0.010

L 0.356 0.610 0.014 0.024

SOT- 25 Surface Mount Package

RT9168/A

DS9168/A-03 May 2001 www.richtek-ic.com.tw

Dimensions In Millimeters Dimensions In Inches

Symbol Min Max Min Max

A 4.801 5.004 0.189 0.197

B 3.810 3.988 0.150 0.157

C 1.346 1.753 0.053 0.069

D 0.330 0.508 0.013 0.020

F 1.194 1.346 0.047 0.053

H 0.178 0.254 0.007 0.010

I 0.102 0.254 0.004 0.010

J 5.791 6.198 0.228 0.244

M 0.406 1.270 0.016 0.050

8–Lead SOP Plastic Package

D I

RT9168/A

DS9168/A-03 May 2001 www.richtek-ic.com.tw

RICHTEK TECHNOLOGY CORP.

Headquarter

6F, No. 35, Hsintai Road, Chupei City

Hsinchu, Taiwan, R.O.C.

Tel: (8863)5510047 Fax: (8863)5537749

RICHTEK TECHNOLOGY CORP.

Taipei Office (Marketing)

8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City

Taipei County, Taiwan, R.O.C.

Tel: (8862)89191466 Fax: (8862)89191465

Email: marketing@richtek-ic.com.tw