March 2000

1

MIC39300/39301

MIC39300/39301

Micrel

MIC39300/39301

3A Low-Voltage Low-Dropout Regulator

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

General Description

The MIC39300 and MIC39301 are 3.0A low-dropout linear

voltage regulators that provide a low voltage, high-current

output with a minimum of external components. Utilizing

Micrel’s proprietary Super

βeta PNP™ pass element, the

MIC39300/1 offers extremely low dropout (typically 400mV at

3.0A) and low ground current (typically 36mA at 3.0A).

The MIC39300/1 is ideal for PC add-in cards that need to

convert from standard 5V or 3.3V down to new, lower core

voltages. A guaranteed maximum dropout voltage of 500mV

over all operating conditions allows the MIC39300/1 to pro-

vide 2.5V from a supply as low as 3V. The MIC39300/1 also

has fast transient response for heavy switching applications.

The device requires only 47

µF of output capacitance to

maintain stability and achieve fast transient response

The MIC39300/1 is fully protected with overcurrent limiting,

thermal shutdown, reversed-battery protection, reversed-

leakage protection, and reversed-lead insertion. The

MIC39301 offers a TTL-logic compatible enable pin and an

error flag that indicates under voltage and over current

conditions. Offered in fixed voltages, the MIC39300/1 comes

in the TO-220 and TO-263 packages and is an ideal upgrade

to older, NPN-based linear voltage regulators.

Typical Application

MIC39300-2.5

IN

OUT

GND

47µF

3.3V

2.5V

MIC39300

Features

• 3.0A minimum guaranteed output current

• 500mV maximum dropout voltage over temperature

Ideal for 3.0V to 2.5V conversion

• 1% initial accuracy

• Low ground current

• Current limiting and Thermal shutdown

• Reversed-battery protection

• Reversed-leakage protection

• Fast transient response

• TO-263 and TO-220 packaging

• TTL/CMOS compatible enable pin (MIC39301 only)

• Error flag output (MIC39301 only)

Applications

• LDO linear regulator for PC add-in cards

• High-efficiency linear power supplies

• SMPS post regulator

• Multimedia and PC processor supplies

• Low-voltage microcontrollers

• StrongARM™ processor supply

StrongARM is a trademark of Advanced RISC Machines, Ltd.

Ordering Information

Part Number

Voltage

Junction Temp. Range

Package

MIC39300-2.5BT

2.5V

–40

°C to +125°C

3-lead TO-220

MIC39300-2.5BU

2.5V

–40

°C to +125°C

3-lead TO-263

MIC39301-2.5BT

2.5V

–40

°C to +125°C

5-lead TO-220

MIC39301-2.5BU

2.5V

–40

°C to +125°C

5-lead TO-263

MIC39301-2.5

IN

OUT

GND

47µF

3.3V

2.5V

EN

FLG

ERROR FLAG

OUTPUT

ENABLE

SHUTDOWN

100k

Ω

MIC39301