Ring CMOS not-based oscillators: Analysis and design

Abstract

This paper presents design hints in CMOS ring oscillators based on NOT gates. The NOT gate is used as vehicle to introduce basics on signal propagation and also to present simple design models. Both simulation and experimental results are presented in order to show the usefulness of the design models. However, for high frequency oscillators several design strategies that are translated at layout level are also described not only to minimize undesirable effects, but also for testing the circuit under study (CUS).