In definition, an electronic oscillator is an electronic system consisting of active and passive circuit elements to produce a periodic signal at the output without the application of an external input signal [1]. Because an oscillator itself generates a periodic signal, specifically a clock signal, the spectral purity of the signal highly depends on the quality of the oscillator. Even a standalone oscillator can serve as a clocking circuit depending on the system requirement. Therefore, a CMOS oscillator is the most important building block of a CMOS clocking circuit that should be studied in depth. This chapter will introduce fundamentals of two popular CMOS oscillator topologies: LC oscillator and ring oscillator.

Chapter Contents:

• 3.1 LC oscillator
• 3.2 Ring oscillator
• 3.3 Appendix: Translation of series R-L to parallel R-L
• References

Inspec keywords: CMOS analogue integrated circuits; phase noise; oscillators; low-power electronics; clocks

Other keywords: ring oscillator; system requirement; CMOS oscillator topologies; electronic oscillator; CMOS clocking circuit; periodic signal; active circuit elements; spectral purity; clock signal; standalone oscillator; electronic system; passive circuit elements; LC oscillator; external input signal

Subjects: CMOS integrated circuits; Oscillators