General Description

The MAX8581/MAX8582 high-frequency step-down converters are optimized for dynamically powering the power amplifier (PA) in CDMA handsets. They integrate a highefficiency PWM step-down converter for medium- and low-power transmission and a 60mΩ (typ) bypass mode to power the PA directly from the battery during high power transmission. They use an analog input driven by an external DAC to control the output voltage linearly for continuous PA power adjustment. The MAX8581/MAX8582 use an internal feedback network, and the switching frequency is internally set to 2.5MHz and 1.5MHz, respectively.

Features

♦ 600mA Step-Down Converter

♦ 60mΩ (typ) Bypass Mode with Integrated FET

♦ Dynamically Adjustable Output from 0.4V to VIN

♦ 2.5MHz and 1.5MHz Switching Frequency

♦ Small LC Components: 1.5µH to 3.3µH and 2.2µF

♦ Up to 94 Efficiency

♦ Low Output Ripple at All Loads

♦ 2.7V to 5.5V Input

♦ 0.1µA Shutdown Mode

♦ Output Short-Circuit Protection

♦ Thermal Shutdown

♦ 10-Pin, 3mm x 3mm TDFN Packages

Applications

    WCDMA/NCDMA Cell Phones

    Wireless PDAs, Smartphones