A Comprehensive Phase Noise Analysis of Bang-Bang Digital PLLs
Abstract
This work introduces an accurate linearized model and phase noise spectral analysis of digital bang-bang PLLs, that includes both the reference and the digitally-controlled oscillator (DCO) noise contributions. A time-domain analysis of bang-bang PLLs is leveraged to derive closed-form expressions for the integrated jitter, leading to a precise estimation of the binary phase detector (BPD) equivalent gain. The theoretical predictions differ by less than 1% from the simulation results obtained using a behavioral model, in all typical cases: dominant reference noise, dominant DCO noise, and comparable contributions. An accurate discrete-time model that takes into account the time-variant effect arising from the multirate nature of a digital phase-locked loop (DPLL) is used, along with the provided estimation of the jitter, to predict the output and input-referred phase noise spectra. An excellent match with the simulated spectra is achieved for all the different operating conditions.
Publication Title
IEEE Transactions on Circuits and Systems I: Regular Papers
Recommended Citation
Avallone, L., Mercandelli, M., Santiccioli, A., Kennedy, M., Levantino, S., & Samori, C. (2021). A Comprehensive Phase Noise Analysis of Bang-Bang Digital PLLs. IEEE Transactions on Circuits and Systems I: Regular Papers, 68 (7), 2775-2786. https://doi.org/10.1109/TCSI.2021.3072344
