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ISSUE 5 - NOVEMBER 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

1

DESCRIPTION

The ZXCL series are  very small low dropout

regulators designed for use in low power and

severely space limited applications.

The devices operate with a low dropout voltage,

typically of only 85mV at 50mA load. Supply current

is minimised with a ground pin current of only 50

µ

A

at full 150mA load. Logic control allows the devices

to be shut down, consuming typically less than 10nA.

These features make the device ideal for battery

powered applications where power economy is

critical.

The parts have been designed with space sensitive

systems in mind. They are available in the ultra small

SC70 package, which is half the size of other SOT23

based regulator devices.

FEATURES

5-pin SC70 package for the ultimate in space

saving

5-pin SOT23 industry standard pinout

Low 85mV dropout at 50mA load

50

µ

A ground pin current with full 150mA load

Typically less than 10nA ground pin current on

shutdown

2.5, 2.6, 2.8, 3, 3.3 and 4 volts output

Very low noise, without bypass capacitor

Thermal overload and over-current protection

-40 to +85°C operating temperature range

For applications requiring improved performance

over alternative devices, the ZXCL is also offered in

the 5 pin SOT23 package with an industry standard

pinout.

The devices feature thermal overload and

over-current protection and are available with output

voltages of 2.5V, 2.6V, 2.8V, 3V,  3.3V and 4V. Other

voltage options between 1.5V and 4V can be

provided. Contact Zetex marketing for further

information.

The ZXCL series are manufactured using CMOS

processing, however advanced design techniques

mean that output noise is  improved even when

compared to other bipolar devices.

APPLICATIONS

Cellular and Cordless phones

Palmtop and laptop computers

PDA

Hand held instruments

Camera, Camcorder, Personal Stereo

PCMCIA cards

Portable and Battery-powered equipment

ULTRA SMALL MICROPOWER SC70 LOW DROPOUT REGULATORS

Battery Supply

Output Voltage

ZXCL

TYPICAL APPLICATION CIRCUIT

PACKAGE FOOTPRINT

Total Aea

2.1mm x 2mm

=4.2mm

2

Total Aea

2.8mm x 2.9mm

=8.12mm

2

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2

ISSUE 5 - NOVEMBER 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

ABSOLUTE MAXIMUM RATINGS

Terminal Voltage with respect to GND

V

IN

-0.3V to 7.0V

E

N

-0.3V to 10V

V

O

-0.3V to 5.5V

Output short circuit duration

Infinite

Continuous Power Dissipation

Internally limited

Operating Temperature Range

-40°C to +85°C

Storage  Temperature Range

-55°C to +125°C

ELECTRICAL CHARACTERISTICS

V

IN

= V

O

+ 0.5V, typical values at TA = 25 C V (Unless otherwise stated)

SYMBOL

PARAMETER

CONDITIONS

LIMITS

UNITS

MIN

TYP

MAX

V

IN

Input Voltage

(note2)

5.5

V

V

O

Output Voltage

I

O

= 1mA

ZXCL250

ZXCL260

ZXCL280

ZXCL300

ZXCL330

ZXCL400

I

O

= 100mA

V

O

+ 0.5V < V

IN

< V

IN

max.

ZXCL250

ZXCL260

ZXCL280

ZXCL300

ZXCL330

ZXCL400

2.450

2.548

2.744

2.940

3.234

3.920

2.425

2.522

2.744

2.910

3.201

3.880

2.5

2.6

2.8

3.0

3.3

4.0

2.550

2.652

2.856

3.060

3.366

4.080

2.575

2.678

2.884

3.090

3.399

4.120

V

V

V

O

/

T

Output Voltage

Temperature

Coefficient

-15

ppm/°C

I

O(MAX)

Output Current

ZXCL250 only

150

100

mA

I

OLIM

Over Current Limit

ZXCL250 only

160

105

230

800

750

mA

I

Q

Ground pin current

No Load

I

O

= 150mA,

I

O

= 100mA,

25

50

40

50

120

100

␮A

␮A

␮A

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the

device. These are stress ratings only, and functional operation of the device at these or any other conditions

beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute

maximum conditions for extended periods may affect device reliability.

Package Power Dissipation (T

A

=25°C)

SC70

300mW (Note 1)

SOT23-5

450mW (Note 1)

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ELECTRICAL CHARACTERISTICS

V

IN

= V

O

+ 0.5V, typical values at T

A

=25°C (Unless otherwise stated)

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

ISSUE 5 - NOVEMBER 2001

3

SYMBOL

PARAMETER

CONDITIONS

LIMITS

UNITS

MIN

TYP

MAX

V

DO

Dropout Voltage

Note 3

ZXCL250

I

O

=10mA

I

O

=50mA

I

O

=100mA

ZXCL260

I

O

=10mA

I

O

=50mA

I

O

=100mA

ZXCL280

I

O

=10mA

I

O

=50mA

I

O

=100mA

ZXCL300

I

O

=10mA

I

O

=50mA

I

O

=100mA

ZXCL330

I

O

=10mA

I

O

=50mA

I

O

=100mA

ZXCL400

I

O

=10mA

I

O

=50mA

I

O

=100mA

15

85

163

15

85

155

15

85

140

15

85

140

15

85

140

15

85

140

325

310

280

280

280

280

mV

mV

mV

mV

mV

mV

⌬V

LNR

Line Regulation

V

IN

=(V

O

+0.5V) to 5.5V, I

O

=1mA

0.02

0.1

%/V

⌬V

LDR

Load Regulation

I

O

=1mA to 100mA

0.01

0.04

%/mA

E

N

Output Noise Voltage

f=10Hz to 100kHz, C

O

=10

µ

F,

50

µ

V rms

V

ENH

Enable pin voltage for

normal operation

T

A

= -40

°

C

2

2.2

10

V

V

ENL

Enable pin voltage for

output shutdown

0

0.8

V

V

ENHS

Enable pin hysteresis

150

mV

I

EN

Enable Pin input

current

V

EN

=5.5V

100

nA

I

QSD

Shutdown supply

current

V

EN

=0V

1

µ

A

T

SD

Thermal Shutdown

Temperature

125

165

°C

Device testing is performed at T

A

=25

ЊC. Device thermal performance is guaranteed by design.

Note1: Maximum power dissipation is calculated assuming the device is mounted on a PCB measuring 2

inches square

Note 2: Output Voltage will start to rise when V

IN

exceeds a value or approximately 1.3V. For normal

operation, V

IN

(min) > V

OUT

(nom) + 0.5V.

Note 3: Dropout voltage is defined as the difference between V

IN

and V

O

, when V

O

has dropped 100mV below

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4

-50

-25

0

25

50

75

100

2.79

2.80

2.81

-50

-25

0

25

50

75

100

23.0

23.2

23.4

23.6

23.8

24.0

24.2

24.4

24.6

24.8

25.0

0

1

2

3

4

5

0

5

10

15

20

25

30

0

25

50

75

100

125

150

20

25

30

35

40

45

50

55

60

0

1

2

3

4

5

6

0

1

2

3

4

5

6

0

25

50

75

100

125

150

175

0.00

0.05

0.10

0.15

0.20

0.25

V

IN

= 3.3V

No Load

Output Voltage v Temperature

Output

Voltage

(V)

Temperature (°C)

V

IN

= 3.3V

No Load

Ground Current v Temperature

Gr

ound

Cur

rent

(µA)

Temperature (°C)

No Load

Ground Current v Input Voltage

Gr

ound

Cur

rent

(µA)

Input Voltage (V)

V

IN

= 3.3V

V

IN

= 5V

Ground Current v Load Current

Gr

ound

Cur

rent

(µA)

Load Current (mA)

V

IN

I

OUT

= 100mA

I

OUT

= 1mA

Input to Output Characteristics

Volt

age

(V

)

Input Voltage (V)

Dropout Voltage v Output Current

D

ropout

Voltage

(V)

Output Current (mA)

ISSUE 5 - NOVEMBER 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

TYPICAL CHARACTERISTICS

(ZXCL280 shown)

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ISSUE 5 - NOVEMBER 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

5

0.0

0.1

0.2

0.3

0.4

0.5

-20

-10

0

10

20

3

4

5

6

0

10

20

30

40

50

60

70

80

90

100

0

1

2

3

4

5

6

0.0

0.1

0.2

0.3

0.4

0.5

-20

-10

0

10

20

3

4

5

6

0.0

0.1

0.2

0.3

0.4

0.5

-100

-50

0

50

100

0

50

100

10

100

1k

10k

100k

1M

0.01

0.1

1

10

10

100

1k

10k

100k

1M

0

10

20

30

40

50

60

70

80

C

OUT

= 1

mF

T

r

& T

f

= 2.5

ms

Line Rejection I

L

= 100mA

D

V

OUT

(mV)

V

IN

(V)

Time (ms)

V

IN

= 5V

I

L

= 1mA

I

L

= 100mA

Enable

V

IN

= 3.3V

I

L

= 1mA

I

L

= 100mA

C

OUT

= 1

mF

Start-Up Response

Voltage

(V)

Time (

µ

s)

C

OUT

= 1

mF

T

r

& T

f

= 2.5

ms

D

V

OUT

(mV)

V

IN

(V)

Line Rejection I

L

= 1mA

Time (ms)

C

OUT

= 10

mF

C

OUT

= 1

mF

C

OUT

= 10

mF

C

OUT

= 1

mF

V

IN

= 5V

I

L

= 1mA to 50mA

Load Response

D

V

OUT

(mV)

I

L

(mA)

Time (ms)

I

L

= 100mA, C

OUT

= 1

mF

I

L

= 100mA, C

OUT

= 10

mF

No Load, C

OUT

= 10

mF

No Load, C

OUT

= 1

mF

Output Noise v Frequency

Noise

µ

V/

Hz

Frequency (Hz)

All Caps Ceramic

Surface Mount

I

L

= 50mA

C

OUT

= 1

mF

C

OUT

= 2.2

mF

C

OUT

= 10

mF

Power Supply Rejection v Frequency

Power

Supply

Rejection

(dB)

Frequency (Hz)

TYPICAL CHARACTERISTICS

(ZXCL280 shown)

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ISSUE 5 - NOVEMBER 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

6

PIN DESCRIPTION

Pin Name

Pin Function

V

IN

Supply Voltage

G

ND

Ground

E

N

Active HIGH Enable input. TTL/CMOS logic compatible.

Connect to V

IN

or logic high for normal operation

N/C

No Connection

V

O

Regulator Output

SC70

Package Suffix – H5

Top View

SOT23-5

Package Suffix – E5

Top View

G

ND

E

N

N/C

V

IN

V

O

1

2

3

4

5

G

ND

E

N

N/C

V

IN

V

O

1

2

3

4

5

CONNECTION DIAGRAMS

SCHEMATIC DIAGRAM

SC70

Package Suffix –H5

Top View

G

ND

E

N

N/C

V

IN

V

O

1

2

3

4

5

ZXCLXXX

ZXCL1XXX

ZXCLXXX

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Input to Output Diode

In common with many other LDO regulators, the ZXCL

device has an inherent diode associated with the

output series pass transistor of each regulator. This

diode has its anode connected to the output and its

cathode to the input. The internal diode is normally

reverse biased, but will conduct if the output is forced

above the input by more than a V

BE

(approximately

0.6V). Current will then flow from Vout to Vin. For safe

operation, the maximum current in this diode should

be limited to 5mA continuous and 30mA peak. An

external schottky diode may be used to provide

protection when this condition cannot be satisfied.

Increased Output current

Any ZXCL series device may be used in conjunction

with an external PNP transistor to boost the output

current capability. In the application circuit

shown

below, a FMMT717 device is employed as the external

pass element. This SOT23 device can supply up to 2.5A

maximum current subject to the thermal dissipation

limits of the package (625mW). Alternative devices

may be used to supply higher levels of current. Note

that with this arrangement, the dropout voltage will be

increased by the VBE drop of the external device. Also,

care should be taken to protect the pass transistor in

the event of excessive output current.

ISSUE 5 - NOVEMBER 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

7

VIN

EN

GN

D

VO

U1

ZXCL SERIES

Q1

FMMT717

R1

5.6R

C2

1uF

C1

1uF

C3

1uF

VOUT

VIN

Scheme to boost output current to 2A

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APPLICATIONS INFORMATION

Enable Control

A TTL compatible input is provided to allow the

regulator to be shut down. A low voltage on the Enable

pin puts the device into shutdown mode. In this mode

the regulator circuit is switched off and the quiescent

current reduces to virtually zero (typically less than

10nA). A high voltage on the Enable pin ensures

normal operation.

The Enable pin can be connected to V

IN

or driven from

an independent source of up to 10V maximum. (e.g.

CMOS logic) for normal operation. There is no clamp

diode from the Enable pin to V

IN

, so the V

IN

pin may be

at any voltage within its operating range irrespective of

the voltage on the Enable pin.

Current Limit

The ZXCL devices include a current limit circuit which

restricts the maximum output current flow to typically

230mA. Practically the range of over-current should be

considered as minimum 160mA to maximum 800mA.

The device’s robust design means that an output short

circuit to any voltage between ground and V

OUT

can be

tolerated for an indefinite period.

Thermal Overload

Thermal overload protection is included on chip. When

the device junction temperature exceeds a minimum

125°C the device will shut down. The sense circuit will

re-activate the output as the device cools. It will then

cycle until the overload is removed. The thermal

overload protection will be activated when high load

currents or high input to output voltage differentials

cause excess dissipation in the device.

Start up delay

A small amount of hysteresis is provided on the Enable

pin to ensure clean switching. This feature can be used

to introduce a start up delay if required. Addition of a

simple RC network on the Enable pin provides this

function. The following diagram illustrates this circuit

connection. The equation provided enables calculation

of the delay period.

ISSUE 5 - NOVEMBER 2001

8

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

R

C

Figure 1 Circuit Connection

T

d

T

= RCIn

V

V

1.5

d(NOM)

IN

IN

Calculation of start up delay as above

Figure 2 Start up delay (T

d

)

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APPLICATIONS INFORMATION (Cont)

Power Dissipation

The maximum allowable power dissipation of the

device for normal operation (Pmax), is a function of the

package junction to ambient thermal resistance (

θ

ja),

maximum junction temperature (Tjmax), and ambient

temperature (Tamb), according to the expression:

P

max

= (Tj

max

– T

amb

) /

θ

ja

The maximum output current (I

max

) at a given value of

Input voltage (V

IN

) and output voltage (V

OUT

) is then

given by

I

max

= P

max

/ (V

IN

- V

OUT

)

The value of

θ

ja is strongly dependent upon the type of

PC board used. Using the SC70 package it will range

from approximately 280 °C/W for a multi-layer board to

around 450°C/W for a single sided board. It will range

from 180°C/W to 300°C/W for the SOT23-5 package. To

avoid entering the thermal shutdown state, Tj

max

should be assumed to be 125°C and I

max

less than the

over-current limit,(I

OLIM

). Power derating for the SC70

and SOT23-5 packages is shown in the following

graph.

Capacitor Selection and Regulator Stability

The device is designed to operate with all types of

output capacitor, including tantalum and low ESR

ceramic. For stability over the full operating range from

no load to maximum load, an output capacitor with a

minimum value of 1

µ

F is recommended, although this

can be increased without limit to improve load

transient performance. Higher values of output

capacitor will also reduce output noise. Capacitors with

ESR less than 0.5

are recommended for best results.

An input capacitor of 1

µ

F (ceramic or tantalum) is

recommended to filter supply noise at the device input

and will improve ripple rejection.

The input and output capacitors should be positioned

close to the device, and a ground plane board layout

should be used to minimise the effects of parasitic track

resistance.

Dropout Voltage

The output pass transistor is a large PMOS device,

which acts like a resistor when the regulator enters the

dropout region. The dropout voltage is therefore

proportional to output current as shown in the typical

characteristics.

Ground Current

The use of a PMOS device ensures a low value of

ground current under all conditions including dropout,

start-up and maximum load.

P o w e r S u p p l y R e j e c t i o n a n d L o a d

Transient Response

Line and Load transient response graphs are shown in

the typical characteristics.

These show both the DC and dynamic shift in the

output voltage with step changes of input voltage and

load current, and how this is affected by the output

capacitor.

If improved transient response is required, then an

output capacitor with lower ESR value should be used.

Larger capacitors will reduce over/undershoot, but will

increase the settling time. Best results are obtained

using a ground plane layout to minimise board

parasitics.

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

9

-40

-20

0

20

40

60

80

100

0

100

200

300

400

500

SOT23

SC70

Derating Curve

Max

Power

D

issipation

(mW)

Temperature (°C)

ISSUE 5 - NOVEMBER 2001

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ISSUE 5 - NOVEMBER 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

10

PACKAGE DIMENSIONS

SC70

DIM

Millimetres

MIN

MAX

A

1.00

A1

0.10

A2

0.70

b

0.15

C

0.08

D

2.00BSC

E

2.10BSC

E1

1.25BSC

e

0.65BSC

e1

1.30BSC

L

0.26

0.46

0

8

SOT23-5

DIM

Millimetres

MIN

MAX

A

0.90

1.45

A1

0.00

0.15

A2

0.90

1.3

b

0.35

0.50

C

0.09

0.20

D

2.80

3.00

E

2.60

3.00

E1

1.50

1.75

e

0.95 REF

e1

1.90 REF

L

0.10

0.60

0

10

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ISSUE 5 - NOVEMBER 2001

Zetex plc

Fields New Road

Chadderton

Oldham, OL9 8NP

United Kingdom

Telephone (44) 161 622 4422

Fax: (44) 161 622 4420

Zetex GmbH

Streitfeldstraße 19

D-81673 München

Germany

Telefon: (49) 89 45 49 49 0

Fax: (49) 89 45 49 49 49

Zetex Inc

700 Veterans Memorial Hwy

Hauppauge, NY11788

USA

Telephone: (631) 360 2222

Fax: (631) 360 8222

Zetex (Asia) Ltd

3701-04 Metroplaza, Tower 1

Hing Fong Road

Kwai Fong, Hong Kong

China

Telephone: (852) 26100 611

Fax: (852) 24250 494

These offices are supported by agents and distributors in major countries world-wide.

This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or

reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services

concerned. The Company reserves the right to alter without notice the specification, design, price or conditions of supply of any product or

service.

For the latest product information, log on to

www.zetex.com

© Zetex plc 2001

ZXCL250 ZXCL260 ZXCL280

ZXCL300 ZXCL330 ZXCL400

11

ORDERING INFORMATION

DEVICE

Output

Voltage

V

Package

Partmarking

ZXCL250H5

2.5

SC70

L25A

ZXCL260H5

2.6

SC70

L26A

ZXCL280H5

2.8

SC70

L28A

ZXCL300H5

3.0

SC70

L30A

ZXCL330H5

3.3

SC70

L33A

ZXCL400H5

4.0

SC70

L40A

ZXCL1250H5

2.5

SC70

L25C

ZXCL1260H5

2.6

SC70

L26C

ZXCL1280H5

2.8

SC70

L28C

ZXCL1300H5

3.0

SC70

L30C

ZXCL1330H5

3.3

SC70

L33C

ZXCL1400H5

4.0

SC70

L40C

ZXCL250E5

2.5

SOT23-5

L25B

ZXCL260E5

2.6

SOT23-5

L26B

ZXCL280E5

2.8

SOT23-5

L28B

ZXCL300E5

3.0

SOT23-5

L30B

ZXCL330E5

3.3

SOT23-5

L33B

ZXCL400E5

4.0

SOT23-5

L40B