Fairchild Semiconductor's RF Power DC-DC Converter Provides Industry's Smallest Power Management Solution for W-CDMA/CDMA RFPAs in 3G Handsets

This converter helps to extend talk-time by up to 40 minutes in 3G handsets by adapting the voltage supply level of the 3G RF power amplifier according to the RF power sent through the antennae, enabling higher power efficiency for a wide range of antenna power levels. This results in up to 100mA of battery current consumption savings in data-centric and smart phones especially in suburban and poor coverage areas. This feature enables 20 to 30 percent more power, dramatically extending connection time and allowing 3G handsets to run more processor applications. In addition, the FAN5902 offers up to 800mA rms current output capability to service excessive RF PA current resulting from strong antenna mismatch and a 50 milliohm on resistance bypass FET, enabling operation down to 2.7 volts.

The FAN5902 also addresses the key problem of overheating in the RF power amplifier, especially at high battery voltage. Since the FAN5902 scales down the RFPA supply voltage, reducing its heating by 20 to 40 percent, the heat sink can be shrunk and the component density can be increased, reducing weight, cost and size.

Fairchild Semiconductor continues to innovate mobile designs with its wide range of solutions that answer compelling design challenges of increasing efficiency, reducing board space, preserving signal fidelity and simplifying design. This includes the FAN5355, an 800mA/1000mA, 3MHz Buck converter, developed for powering core graphics and application processors in handheld applications where footprint, wide-range efficiency and performance are important, and the FAN5361, a 6MHz, 600mA Buck converter that offers an optimal balance between efficiency and size for portable applications.