Phase noise in inverter-based & amp; differential CMOS ring oscillators

Abstract

Simple but precise expressions are derived for jitter, and thus for phase noise, in inverter-based and differential ring oscillators. White and flicker noise are included. The expressions are validated by measurement and simulation.

The effect of noise propagation on phase noise in ring oscillators

“…In this paper we demonstrate how white noise can in fact propagate to succeeding delay cells depending on the shape of the oscillating waveform. This effect will result in additional jitter not predicted by the existing models for ring oscillators [1,2]. We will then show how, contrary to commonly-held assumptions, the resulting phase noise and jitter can depend on the number of stages.…”

“…Even though ring oscillators have been widely used in both analog and digital applications for decades, the study of their phase noise and jitter behavior is still a topic of active research [1][2][3]. While Hajimiri and Lee have used the concept of impulse sensitivity functions to characterize the phase noise of ring oscillators [3], Abidi and Samadian have utilized a relationship between jitter and phase noise and have then analyzed each noise source independently using direct circuit parameters.…”

“…It has been observed from the analysis of jitter resulting from flicker noise sources that any positive correlation in the noise sources can potentially increase the jitter compared to when the noise sources are uncorrelated [1].…”

“…al. have used interchangeable time and frequency domain formulas to come up with equations that model the phase noise and jitter of such oscillators [1,2]. In this analysis, the phase noise due to white and flicker noise sources are treated separately due to their different natures in affecting the jitter.…”

Wake-up Receiver Based Ultra-Low-Power WBAN

“…For the ring oscillator the phase noise model was presented in [59] and extended in [56], respectively. The quality factor Q for the LC oscillator is approximately equal to the quality factor of the tank inductor.…”