High efficiency GaN HEMT switching device with integrated driver for envelope tracking modulators

MMIC design and fabrication of a new highly efficient and high speed switching device are proposed. This switching cell, composed of a floating source power transistor (Normally-ON GaN HEMT) along with its gate driver, is able to provide output power up to 100W with a switching frequency up to 500MHz and output voltage slew rate in the order of 100V/ns. Then, a supply modulator for envelope tracking systems is presented, based on the MMIC switching cell. This modulator uses a 120MHz PWM frequency with a 17MHz reconstruction filter. It exhibits an output voltage up to 50V on a 50Ω load with an average efficiency over 80%.