An efficient and accurate procedure to evaluate distortion in SOI FD MOSFET

The total harmonic distortion (THD) and the third harmonic distortion (HD3) of the output current-voltage characteristics of SOI FD MOSFET is calculated using a new integral method. The method is based on the calculation of two functions, which we call D and D3 and are based on a specific integration of the DC current-voltage characteristic of the device. We demonstrate that function D can be related with the THD and function D3 with the HD3, so that both THD and HD3 can be determined in a much simpler way, with no need to use derivatives, Fourier coefficients or Fast Fourier Transforms. The new method is applied to calculate the harmonic distortion of a SOI FD MOS transistor in the triode regime, when used as an active resistor at the input of an operational amplifier in a MOSFET-C filter configuration. It is also demonstrated that the values of THD and HD3 obtained in a very simple and straightforward way by our new method have an excellent coincidence with values obtained by calculating Fourier coefficients for experimental, simulated or calculated I_DS-V_DS characteristics and with AC measured values