Modelling, decoupling and suppression of MOSFET distortion components

The author presents an analysis of the dominant distortion components of the drain current of a long-channel MOSFET in nonsaturation, which accounts explicitly for the modulation of the inversion layer mobility by transverse electric fields and for all bias and relevant process (SPICE) parameters. This model predicts that if the gate is driven by a linear and by a parabolic signal (α₁V_D+α₂V_D² ), both derived from the drain signal V_D, odd and even distortion components are decoupled and simultaneously suppressed by separately setting the constants α₁ and α₂ under normal bias conditions. In prior methods, these components are strongly coupled and their suppression requires a delicate body bias or signal (βV_D) adjustment to offset the signal-dependent mobility modulation, which is impractical in monolithic applications. These predictions are confirmed by Fourier analysis and by SPICE simulations provided the mobility modulation parameter matches experimental observations