MIC5255

150mA Low Noise µCap CMOS LDO

IttyBitty is a registered trademark of Micrel, Inc

MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

November 2006

1

M9999-110906

General Description

The MIC5255 is an efficient, precise CMOS voltage

regulator optimized for ultra-low-noise applications. It

offers 1% initial accuracy, extremely-low dropout voltage

(135mV at 150mA) and low ground current (typically

90µA). The MIC5255 provides a very-low-noise output,

ideal for RF applications where a clean voltage source is

required. A noise bypass pin is also available for further

reduction of output noise.

Designed specifically for handheld and battery-powered

devices, the MIC5255 provides a TTL-logic-compatible en-

able pin. When disabled, power consumption drops nearly

to zero.

The MIC5255 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, faster

transient response, and an active clamp to speed up

device turn-off. Available in the 6-pin 2mm × 2mm MLF

®

package, the IttyBitty

Thin SOT-23-5, which offers the same footprint as the

standard IttyBitty

®

SOT-23-5, but only 1mm tall. The

MIC5255 offers a range of output voltages.

Data sheets and support documentation can be found on

Micrel’s web site at www.micrel.com.

Features

• Input voltage range: 2.7V to 6.0V

• Thin SOT package: 1mm height SOT-23-5

• Ultra-low output noise: 30µV(rms)

• Stability with ceramic output capacitors

• Ultra-low dropout: 135mV @ 150mA

• High output accuracy:

–

1.0% initial accuracy

–

2.0% over temperature

• Low quiescent current: 90µA

• Tight load and line regulation

• TTL-Logic-controlled enable input

• “Zero” off-mode current

• Thermal shutdown and current limit protection

Applications

• Cellular phones and pagers

• Cellular accessories

• Battery-powered equipment

• Laptop, notebook, and palmtop computers

• Consumer/personal electronics

___________________________________________________________________________________________________________

Typical Application

Ceramic

Ceramic

15

2

3

4

Enable

Shutdown

EN

MIC5255-x.x_M5

EN (pin 3) may be

connected directly

to IN (pin 1).

Ultra-Low-Noise Regulator Application