General Description

The Micrel MIC2245 is a high efficiency 4MHz pulse width modulated (PWM) synchronous buck (stepdown) regulator that features a LOWQ™ LDO standby mode that draws only 18µA of quiescent current. The MIC2245 allows an ultra-low noise, small size, and high efficiency solution for portable power applications.

Features

• 2.7 to 5.5V supply/input voltage

• Light load LOWQ™ LDO mode

20µA quiescent current

Low noise, 75µVrms

• 4MHz PWM mode

Output current to 500mA

>92 efficiency

100 maximum duty cycle

• Adjustable output voltage option down to 1V

Fixed output voltage options available

• Ultra-fast transient response

• Uses a tiny 1µH inductor

• Fully integrated MOSFET switches

• Micropower shutdown operation

• Thermal shutdown and current limit protection

• Pb-free 10-pin 3mm x 3mm MLF™ package

• –40°C to +125°C junction temperature range

Applications

• Cellular phones

• PDAs

• USB peripherals