MIC2203

High Efficiency 1MHz Synchronous

Buck Regulator

General Description

The Micrel MIC2203 is a high efficiency 1MHz PWM

synchronous buck switching regulator. The MIC2203

features low noise constant frequency PWM

operation with a low dynamic supply current of

<1mA. The low noise and efficient operation both

make the MIC2203 well suited for sensitive RF, and

audio power applications.

The MIC2203 operates from 2.3V to 5.5V input and

can supply over 300mA of output current with output

voltages down to 0.5V. Additionally, the MIC2203

can be synchronized to an external clock, or multiple

MIC2203s can easily be daisy-chained with the

SYNCLOCK feature.

The MIC2203 has a high loop bandwidth with

corresponding ultra fast transient response times.

This reduces the output capacitor size, and is very

useful when powering applications that require fast

dynamic response such as CPU cores and RF

circuitry in high performance cellular phones and

PDAs.

The MIC2203 is available in 10-pin MSOP and

3mm x 3mm MLF™-10L package options with an

operating junction temperature range from –40ºC to

125ºC.

Features

• Input voltage range: 2.3V to 5.5V

• Output voltage adjustable down to 0.5V

• 300mA output current

• Constant 1MHz PWM switching frequency

• > 95% efficiency

• < 1mA switching supply current

• < 350µA static quiescent current

• < 1µA shutdown current

• All-ceramic capacitors

• Easily synchronized to external clock

• SYNCLOCK feature to daisy chain multiple

devices

• Thermal shutdown and current limit protection

• 10 pin MSOP, and 3mm x 3mm MLF-10L package

options

• –40ºC to +125ºC junction temperature range

Applications

• 802.11 WLAN modules

• MD players

• MP3 players

_____________________________________________________________________

Typical Application

10nF

10µH

1µF

R2

3.83k

R1

10k

2.2µF

SYNC_IN

SYNC_OUT

2.3V to 5.5V

1.8V

300mA

EN

MIC2203BMM

1

2

3

4

5

10

9

8

7

6

High Efficiency Buck Regulator

MicroLead Frame and MLF are trademarks of Amkor Technologies.

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

December 2004

M9999-120604

(408) 955-1690