Low Phase Noise Ring Oscillator Using Current Steering Technique

G. Gopal, Sri M. Madhusudhan Reddy

Abstract: The design of high performance VCOs has been increasingly more important and still is an active research area. Research on VCOs for the past decade has been concentrated in the areas of higher frequency, lower phase noise, low power, low operating voltage, and increased tuning range. This paper presents the design of CMOS voltage controlled ring oscillator by employing current steering technique. By controlling of coarse or fine controls, the proposed circuit allows limited tuning gain. The lower tuning gain can be less sensitivity voltage which is available at control lines. The proposed delay cell design determining the best possible Configuration for the ring oscillators having the least power consumption and precise delay with lesser sensitivity to the variations in the temperature and supply voltage for frequencies of GHz. Tuning ranges for the proposed multi loop ring oscillator topology have been designed at frequencies from 2.163 GHz to 6.5 GHz in Cadence Virtuoso Tool using 180nm technology with current of 12mA.

Keywords: CMOS, coarse/fine tuning, multiloop, phase noise, ring oscillator, VCO