A 25-dBm high-efficiency digitally-modulated SOI CMOS power amplifier for multi-standard RF polar transmitters

A single-ended digitally-modulated power amplifier (DPA) is demonstrated in a 0.13-mum 1.2-V SOI CMOS technology, to be used in a multistandard RF polar transmitter. The amplitude modulation is done by digitally controlling the number of activated unit amplifiers whose currents are summed at the output. The DPA is designed for multi-mode multi-band functionality by avoiding frequency-selective components, except for the final-stage output matching network. The measured DPA is fully functioning and reliably delivers a 24.9-dBm peak output power at 900 MHz with a maximum power efficiency of 62.7%. It also exhibits similar high-efficiency performance for other carrier frequencies with a reconfigured matching network.