A method to derive an equation for the oscillation frequency of a ring oscillator

Abstract

A new method for deriving an equation for the oscillation frequency of a ring oscillator is proposed. The method is general enough to be used for a variety of types of delay stages. Furthermore, it provides a framework to include various parasitic and secondary effects. The method is used to derive an equation for a common ring oscillator topology. The validity of the method and the resulting equation have been verified through simulation. The oscillation frequencies predicted by the proposed method are more accurate than existing equations and account for more secondary effects.