©

1999 IMP, Inc.

408-432-9100/www.impweb.com

1

Key Features

Applications

x

High-efficiency linear power supplies

x

Post regulator for switching supplies

x

5V to 3.3V linear regulators

x

USB hubs

x

Battery chargers

x

Routers, ISDN/DSL modems

x

Low Dropout Voltage

– 0.8V maximum at 100mA

– 0.95V maximum at 800mA

– 20% lower dropout voltage than “1117”

LDO regulators

x

Guaranteed Low Dropout Voltage at Multiple

Current Levels

x

1% Trimmed 2.5V, 3.0V and 3.3V Outputs

x

Reduced Quiescent Current: 75µA Maximum

x

Short Circuit and Thermal Protection

x

Space Saving SOT-223 Surface Mount Package

x

“1117” Pin Compatible

Block Diagram

–

+

+

–

37_01.eps

GND

1

Ref

IMP37

Thermal

Protection

Error

Amp

Current

Limit

2

Input

3

Out

(Tab)

+

–

IMP3

Lo

V

– 800mA

– 800mA

– 2.5V

, 3.0V and 3.3V Output

The IMP37 series of Low Dropout (LDO) three-terminal voltage regula-

tors feature guaranteed low dropout voltages at currents up to 0.8A. The

IMP37 regulator family dropout voltage is guaranteed to be 0.95V or

lower at 0.8A. At 100mA, the maximum dropout voltage is 0.8V.

Compared with “1117” type LDOs, the IMP37 has a 20% lower dropout

voltage.

Three fixed output voltages are offered: 2.5V, 3.0V and 3.3V. Output volt-

ages are factory trimmed to within 1% of the nominal value.

In addition to low dropout voltages, the IMP37 family features greatly

reduced quiescent operating current. The 75

µA maximum specification

represents an over 100 times improvement over competitive devices.

Devices are short circuit protected, and a thermal protection circuit shuts

the regulator off should the junction temperature exceed 165°C.

The IMP37 is available in low-profile plastic SOT-223 and TO-263

packages and are pin compatible with fixed “1117” devices.