Impact of Process and Temperature Variations on the Design of CMOS Colpitts Oscillators

This paper presents a study of temperature and process sensitivity in CMOS Colpitts oscillator. Based on the analysis of linear and non-linear models, temperature and process sensitivity is derived. The design for temperature compensation and process independent oscillator is based on a clear design methodology, and by taking into consideration all of the parameters that contribute to the deviation of the frequency of oscillation from its nominal value. Using the proposed design methodology, the number of digits required for temperature and process compensation can be estimated early in the design process. Moreover, identifying elements that cause the deviation, allows the designer to develop the required compensation method. Using the proposed design methodology, frequency tuning requirements are derived under restriction of the start-up condition. By defining the process and temperature sensitivity parameters early in the design process, unnecessary design iteration is prevented and time-to-market is reduced.