50 mA, High Voltage,

Micropower Linear Regulator

ADP1720

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibilityis assumedbyAnalogDevicesforitsuse,norforanyinfringementsof patentsorother

rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113

©2007 Analog Devices, Inc. All rights reserved.

FEATURES

Wide input voltage range: 4 V to 28 V

Maximum output current: 50 mA

Low light load current:

28 μA at 0 μA load

35 μA at 100 μA load

Low shutdown current: 0.7 μA

Low dropout voltage: 275 mV @ 50 mA load

Initial accuracy: ±0.5%

Accuracy over line, load, and temperature: ±2%

Stable with small 1μF ceramic output capacitor

Fixed 3.3 V and 5.0 V output voltage options

Adjustable output voltage option: 1.225 V to 5.0 V

Current limit and thermal overload protection

Logic controlled enable

Space-saving thermally enhanced MSOP package

APPLICATIONS

DC-to-DC post regulation

PCMCIA regulation

Keep-alive power in portable equipment

Industrial applications

TYPICAL APPLICATION CIRCUITS

GND

1

8

GND

2

GND

3

GND

4

7

6

GND

IN

OUT

EN

5

ADP1720

FIXED

1µF

1µF

Figure 1. ADP1720 with Fixed Output Voltage, 5.0 V

GND

1

GND

2

GND

3

GND

4

8

7

6

ADJ

IN

OUT

EN

5

ADP1720

ADJUSTABLE

1.225V(1 + R1/R2)

1µF

1µF

R1

R2

Figure 2. ADP1720 with Adjustable Output Voltage, 1.225 V to 5.0 V

GENERAL DESCRIPTION

The ADP1720 is a high voltage, micropower, low dropout linear

regulator. Operating over a very wide input voltage range of 4 V

to 28 V, the ADP1720 can provide up to 50 mA of output current.

With just 28 μA of quiescent supply current and a micropower

shutdown mode, this device is ideal for applications that require

low quiescent current.

The ADP1720 is available in fixed output voltages of 3.3 V and

5.0 V. An adjustable version is also available, which allows the

output to be set anywhere between 1.225 V and 5.0 V. An enable

function that allows external circuits to turn on and turn off the

ADP1720 output is available. For automatic startup, the enable

(EN) pin can be connected directly to the input rail.

The ADP1720 is optimized for stable operation with small 1 μF

ceramic output capacitors, allowing for good transient perform-

ance while occupying minimal board space.

The ADP1720 operates from –40°C to +125°C and uses current

limit protection and thermal overload protection circuits to

prevent damage to the device in adverse conditions.

Available in a small thermally enhanced MSOP package, the

ADP1720 provides a compact solution with low thermal resistance.