The MAX8581/MAX8582 high-frequency step-down converters are optimized for dynamically powering the power amplifier (PA) in CDMA handsets. They integrate a high-efficiency 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. Fast switching (up to 2.5MHz) and fast soft-start allowthe use of ceramic 2.2µF input and output capacitors while maintaining low voltage ripple. The small 1.5µH to 3.3µH inductor size can be optimized for efficiency. The MAX8581/MAX8582 are available in 10-pin, 3mm x3mm TDFN packages (0.8mm max height). Applications * WCDMA/NCDMA Cell Phones * Wireless PDAs, Smartphones * 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