August 2005

1

M9999-082505-B

MIC39100/39101/39102

Micrel

MIC39100/39101/39102

1A Low-Voltage Low-Dropout Regulator

General Description

TheMIC39100,MIC39101,andMIC39102are1Alow-dropout

linearvoltageregulatorsthatprovidelow-voltage,high-current

outputfromanextremelysmallpackage.UtilizingMicrel’spro-

prietary Super βeta PNP™ pass element, the MIC39100/1/2

offers extremely low dropout (typically 410mV at 1A) and low

ground current (typically 11mA at 1A).

The MIC39100 is a fixed output regulator offered in the

SOT-223 package. The MIC39101 and MIC39102 are fixed

and adjustable regulators, respectively, in a thermally en-

hanced power 8-lead SOIC package.

The MIC39100/1/2 is ideal for PC add-in cards that need to

convert from standard 5V to 3.3V, 3.3V to 2.5V or 2.5V to

1.8V.Aguaranteed maximum dropout voltage of 630mV over

all operating conditions allows the MIC39100/1/2 to provide

2.5V from a supply as low as 3.13V and 1.8V from a supply

as low as 2.43V.

The MIC39100/1/2 is fully protected with overcurrent limit-

ing, thermal shutdown, and reversed-battery protection.

Fixed voltages of 5.0V, 3.3V, 2.5V, and 1.8V are available

on MIC39100/1 with adjustable output voltages to 1.24V on

MIC39102.

For other voltages, contact Micrel.

Typical Applications

Features

• Fixed and adjustable output voltages to 1.24V

• 410mV typical dropout at 1A

Ideal for 3.0V to 2.5V conversion

Ideal for 2.5V to 1.8V conversion

• 1A minimum guaranteed output current

• 1% initial accuracy

• Low ground current

• Current limiting and thermal shutdown

• Reversed-battery protection

• Reversed-leakage protection

• Fast transient response

• Low-profile SOT-223 package

• Power SO-8 package

Applications

• LDO linear regulator for PC add-in cards

• PowerPC™ power supplies

• High-efficiency linear power supplies

• SMPS post regulator

• Multimedia and PC processor supplies

• Battery chargers

• Low-voltage microcontrollers and digital logic

Super βeta PNP is a trademark of Micrel, Inc.

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

IN

2.5V

3.3V

10µF

tantalum

OUT

GND

MIC39100

2.5V/1A Regulator

IN

R1

100k

2.5V

Error

Flag

Output

3.3V

10µF

tantalum

EN

OUT

FLG

GND

MIC39101

ENABLE

SHUTDOWN

2.5V/1A Regulator with Error Flag

IN

R1

1.5V

2.5V

10µF

tantalum

R2

EN

OUT

ADJ

GND

MIC39102

ENABLE

SHUTDOWN

1.5V/1A Adjustable Regulator