Characterization of traps in a Power Amplifier using a time domain approach

A time domain characterization of memory effects in an RF amplifier is demonstrated using a simple modification of a conventional two-tone Intermodulation Distortion measurement setup. By constraining the number of RF pulses, thermal effects are minimized. By examining the dynamic gain as a function of tone separation highlights fast traps whereas a study of the dynamic drain current gives insight into the formation of the virtual gate. We observe that both these effects give rise to a gain expansion profile similar to that of a class C amplifier.