Systematic distortion analysis for MOSFET integrators with use of a new MOSFET model

Distortion in MOSFET-based (fixed-capacitance) continuous-time integrators is analyzed. To make the analysis general, the integrators are subdivided into four classes. Almost all the possible MOSFET integrators fall into one of these classes, the rest is mixed class. It is shown that integrators from the same class have the same distortion characteristics. A new method to describe and measure distortion is introduced. Measurement results for the four classes are presented, and for some classes they are explained with a simple MOSFET model. As not all results can be explained this way, a new, highly accurate MOSFET model is introduced. A hint at designing optimal MOSFET´s is given. Finally, it is explained how the distortion characteristics of stages with different MOSFET´s that all contribute to distortion can be determined