Design of CMOS LC Oscillators

Modern RF systems require a stable local oscillation signal at a particular carrier frequency ranging from hundreds of MHz to a few GHz. Designing an oscillator that fulfills the system specification of spectral purity and frequency tuning range under a stringent power consumption limit can be a challenging task especially when using CMOS process targeting a monolithic implementation of the entire RF system. This paper reviews the basic oscillator topologies and design considerations with an emphasis on LC oscillators in CMOS process, discusses some design issues and reports a 3.5-GHz CMOS LC oscillator as a design example