The Design Of High Linearity And Low Phase Noise Oscillator Circuit

With the rapid development of wireless communication technology in recent years, the research and application of CMOS radio frequency integrated circuit and system on chip(SOC) have already become the key trend and hot spots of electronic design nowadays. The CMOS voltage-controlled oscillator (VCO) has turned into a significant component of the phase-locked loop (PLL) circuit in wireless communication area with the foundation of frequency controlled and other features. And the Ring VCO has proved to be used widely with lots of advantages, such as high linearity, wide range of tuning and easier to integrated and the like. The voltage-controlled oscillator not only can provide stable frequency in oscillator circuit, but also the clock signal with high frequency. The research hotpots in the field of VCO in the near future have concentrated on its index of power dissipation, adjustable range, phase noise and other advantages.The paper has analysed models in system theory and special cases in voltage-controlled started from the basic principle and approaches of oscillator, and elaborated the basic framework of LC oscillator and Ring oscillator respectively on the basis of research status of VCO at home and abroad. In addition, the article has finished modeling analysis and brief description aimed at the character of phase noise in oscillator circuit. Considering the above mentioned, the realization of voltage-controlled single-ended delay cell and differential delay circuit in different ways has been analysed emphatically, and a new circuit solution of voltage-controlled with high linearity and low phase noise has been proposed.The voltage-controlled oscillator circuit presented in this paper is achieved by the CMOS technology of TSMC 0.35μm, after the previous simulation of circuit, the layout design have completed with the tool of Virtuoso in Cadence. The outcome after later simulation and verification indicates that the adjustable range of output frequency in oscillator is about 44MHz-163MHz (@1.0V～1.8V). The phase noise is nearly -99.12dBc/Hz at the frequency offset of 100kHz and -128.3dBc/Hz at the frequency offset of 1MHz when the output frequency accesses to 104MHz.