Modeling optical response of the GaAs MESFET using PSpice circuit simulator

In this paper a PSpice model for an illuminated GaAs MESFET is derived. A typical device structure is described and the mechanisms of photoresponse are explained. Photocurrent equations are formulated and implemented in a four-port (one port is “optical”) PSpice subcircuit-illuminated MESFET model. The heart of the subcircuit is a PSpice element GaAs FET. The bias dependence of the photoresponse is carefully considered, so that this subcircuit is suitable for both DC, AC and transient (TRAN) analysis. We give also an application example and a complete subcircuit description in PSpice notation (“.cir” file)