Comparative analysis of various cmos based VCO

Oscillators are integral part of many electronic systems. An oscillator is an electronic device used for the purpose of generating a signal. Almost all digital circuits are dependable on at least one clock source, which generates a rail-to-rail square wave. Applications range from clock generation in microprocessors to carrier synthesis in cellular telephones, requiring vastly different oscillator¿s topologies and performance parameters. Robust, high performance oscillator design in CMOS technology continues to pose interesting challenges. This work deals with the analysis and design of CMOS oscillators more specifically voltage controlled oscillators (VCOs). One of the most critical components in modern communication devices is the VCO. Wireless and mobile communications are two of the fastest growing microelectronics applications, and have an enormous impact on our daily lives. Driven by the insatiable commercial demand for lower cost and higher bandwidth and functionality RF transceivers, wireless communication systems are moving towards higher integration, while operating at higher frequencies