Performance evaluation of commercial GaN RF HEMTs as hybrid topology power switches

This paper describes the potentials and limitations of commercially available bare-die RF GaN HEMTs as a power stage in switch-based supply modulators. The impact of trapping on the efficiency of high frequency switching circuits is investigated by characterizing RF HEMTs as power transistors in a high frequency switching topology. The performance evaluation is based on a comparison of simulation and measured results of a 12 W, and 14 W, synchronous buck converter prototype operating at 10 MHz. Measured efficiency peaks are above 93.1% and 95.8%at 10 MHz and remain above 90% over a wide range of operating conditions. The simulated PAE of the amplifier is improved by 6.5% using dynamic drain bias for input power variation between 16 and 20 dBm. The PAE was improved up to 22 dBm of input power.