MOS resistor modelling for linearity simulation and applications

The aim of this work was to carry out a comparative study of two ideally linear configurations: a MOS resistive circuit (MRC), widely employed in the literature, and a MOS current divider (MCD) based on a linear current division principle. The suitability of some MOS models for distortion simulation purposes is discussed. The general charge-sheet model is used to perform simulations in the MATLAB environment. The harmonic distortion terms are calculated by means of the FFT and the influence of mismatches on the linearity of both cells was estimated. As application, programmable gain amplifiers (PGAs) based on the MRC and the MCD were introduced and their performance in terms of linearity and accuracy was studied and compared.