Remarks on Analysis, Design and Amplitude Stability of MOS Colpitts Oscillator

The small-signal analysis shows that the MOS Colpitts oscillator is described by a third order characteristic equation. The procedure for finding the second order approximation is defined, and the solution corresponding to this approximation is found. Then the equations for transistor transconductance describing function are analyzed, and the design procedure corresponding to the "convenient" operation point is given. The same equations are also used for the analysis of amplitude stability in this oscillator. It is shown that the amplitude self-modulation (squegging) in the considered oscillator is absent for any conducting angle of the transistor.