MIC5247

Micrel, Inc.

February 2006

1

M9999-022406

General Description

The MIC5247 is an efficient and precise, low-voltage CMOS

voltage regulator optimized for ultra-low noise applications.

The MIC5247 offers better than 1% initial accuracy and

85µA constant ground current over load (typically 85µA).

The MIC5247 provides a very low-noise output, ideal for

RF applications where quiet voltage sources are required.

A noise bypass pin is also available for further reduction of

output noise.

Designed specifically for handheld and battery-powered de-

vices, the MIC5247 provides a logic compatible enable pin.

When disabled, power consumption drops nearly to zero.

The MIC5247 also works with low-ESR ceramic capacitors,

reducing the amount of board space necessary for power

applications, critical in handheld wireless devices.

Key features include current limit, thermal shutdown, a push-

pull output for faster transient response, and an active clamp

to speed up device turnoff.Available in the 6-pin 2mm × 2mm

MIC5247 also offers a range of fixed output voltages.

All support documentation can be found on Micrel’s web site

at www.micrel.com.

Typical Application

1

5

2

3

4

Enable

Shutdown

EN

(optional)

MIC5247-x.xBM5

EN (pin 3) may be

connected directly

to IN (pin 1).

MIC5247

150mA Low-Voltage µCap Linear Regulator

Features

• Ultra-low noise

• Low-voltage outputs

• Load independent, ultra-low ground current: 85µA

• 150mA output current

• Current limiting

• Thermal shutdown

• Tight load and line regulation

• “Zero” off-mode current

• Stability with low-ESR capacitors

• Fast transient response

• Logic-controlled enable input

Applications

• Cellular phones and pagers

• Cellular accessories

• Battery-powered equipment

• Laptop, notebook, and palmtop computers

• Consumer/personal electronics

• SMPS post-regulator/DC-to-DC modules

• High-efficiency linear power supplies

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

MIC5247-x.xBML

1

EN

6

(optional)

5

4

2

3

ENABLE

SHUTDOWN

Ultra-Low-Noise Regulator Application