Using “reconciliation” model for calculation of harmonics in a MOS transistor stage operating in moderate inversion

Abstract

The paper describes calculation of the first, second and third harmonics of the output voltage in a MOS transistor stage operating in moderate inversion (common source stage is taken as an example). The dependence of drain current on the gate-source voltage is approximated on the basis of “reconciliation” model proposed by Y. Tsividis and using the term corresponding to saturation operation. Then, the definition of moderate inversion is introduced considering a special series expansion for the function ln2(x). To simplify the calculations we consider the first two terms only for this expansion. Then the harmonic coefficients are obtained by routine calculations. The results of calculations were verified by simulations. The results are in a reasonable agreement; in particular, the presence of the zero value for the third harmonic is confirmed both in calculations and simulations.