A 12.9-to-15.1-GHz Digital PLL Based on a Bang-Bang Phase Detector With Adaptively Optimized Noise Shaping
Simone M. Dartizio, Francesco Tesolin, Mario Mercandelli, Alessio Santiccioli, A. Bahgat Shehata, Saleh Karman, Luca Bertulessi, Francesco Buccoleri, Luca Avallone, Angelo Parisi, Andrea L. Lacaita, Michael Peter Kennedy, Carlo Samori, Salvatore Levantino
Abstract
This work introduces a bang-bang fractional- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> phase-locked loop with quantization noise shaping that overcomes the classical noise limit of a standard bang-bang phase detector. An adaptive algorithm, working in the background of the main system, guarantees optimal noise shaping across process and environmental variations. The prototype, implemented in a standard 28-nm CMOS process, has a core area of 0.21 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and achieves an rms jitter (integrated from 1 kHz to 100 MHz) of 69.5 fs for integer- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> synthesized channels, 79.7 fs for typical fractional- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> channels, and 99.6 fs for near-integer fractional channels with a worst case fractional spur of −51.1 dBc. The power consumption is 10.8 mW, leading to a jitter-power figure of merit of −252.8 dB and −251.6 dB for integer- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> and fractional- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> channels, respectively.