Optimization technique for low phase-noise differential LC VCO design

This paper describes a numerical optimization technique using analytical equations to design cross-coupled differential CMOS LC voltage control oscillator with minimum phase noise. This technique determines optimal VCO design parameters to approach minimum phase-noise with restricted current and limited inductor quality factor. By studying the different noise sources in differential oscillators, the design constraints are induced to achieve the minimum phase-noise and ignore infeasible solutions with taking into account the design specifications. This optimization technique is demonstrated by simulations with good agreement over wide range of frequencies (1 to 5 GHz) through design examples.