20W Doherty Amp Exploits GaN-on-Silicon Design

Targeting broadband and commercial wireless infrastructure markets, the joint efforts of Nitronex and Prescient Wireless take form in a 20W Doherty amplifier employing GaN-on-Si power transistor technology. Based on a Nitronex NPT25100 power transistor, the amplifier delivers 20W of linear power from 2.5 GHz to 2.7 GHz while achieving over 30% efficiency and 2% EVM with digital pre-distortion. Typical performance numbers were taken using a mobile WiMAX waveform defined as single carrier OFDMA 64-QAM, at a 10-MHz channel bandwidth, and 9.5-dB PAR at 0.01% probability during the transmit portion of a 50% duty cycle TDD signal. A reference design is available consisting of the schematic, bill of materials, circuit board layout files, performance data, and other documents describing the design. Finished and tested Doherty application boards are available for $1,950. For more details, call NITRONEX CORP., Durham, NC. (919) 807-9100.