Asynchronous logic for high variability nano-CMOS

At the nanoscale level, parameter variations in fabricated devices cause extreme variability in delay. Delay variations are also the main issue in subthreshold operation. Consequently, asynchronous logic seems an ideal, and probably unavoidable choice, for the design of digital circuits in nano CMOS or other emerging technologies. This paper examines the robustness of one particular asynchronous logic: quasi-delay insensitive or QDI. We identify the three components of this logic that can be affected by extreme variability: staticizer, isochronic fork, and rings. We show that staticizers can be eliminated, and isochronic forks and rings can be made arbitrarily robust to timing variations.