250W HVHBT Doherty with 57% WCDMA Efficiency Linearized to -55dBc for 2c11 6.5dB PAR

A 2-way symmetrical Doherty amplifier exhibiting 250 W saturated power has been developed using High-Voltage HBT (HVHBT) GaAs technology biased at 28 V on the Collector. Greater than 57% collector efficiency at 50W (47dBm) average output power has been demonstrated while achieving -55dBc linearized ACPR at 5 MHz offset using a 2-carrier-side-by-side WCDMA input signal with 6.5dB peak to average ratio measured at .01% probability on the CCDF. At this condition, the measured overall power-added efficiency is 53%. The HVHBT Doherty exhibits 200W (53dBm) PldBat 70% efficiency with 57% efficiency at 6dB output back-off (OBO) from PldB showing a 25 percentage point improvement over class AB operation.