A New Method for CMOS Ring Oscillator Analysis

In this paper, an innovative analytical approach to find oscillation frequency in inverter-based ringoscillators has been proposed. It is shown that the input and output voltages of each stage fall on anelliptical state path. In each part of the path, the transistors operation region of the stage is determinedand the stage equation is written. The time of each working region is calculated using parametricalwaveforms for the input and output voltages. It is concluded that the oscillation period is the sum of allthose time intervals.