Nonlinear HEMT model direct formulated from the second-order derivative of the I–V/ Q-V characteristics

In this paper, an empirical nonlinear model for high electron mobility transistors (HEMTs) is presented. Unlike the conventional large-signal models whose fitting parameters are coupled to the measured I-V and C-V characteristics, the proposed modeling equations are direct formulated from the second-order derivative of drain current (I-V) and gate charge (Q-V) with respect to gate voltage. As a consequence, the proposed large-signal model is kept continuously differentiable and accurate enough to the higher-order I-V and Q-V derivatives. Measured and modeled results are compared for the 0.25 μm gate-length GaAs pseudomorphic HEMTs (pHEMTs), and good agreement is obtained.