Shared-Staticizer for Area-Efficient Asynchronous Circuits

Quasi-Delay-Insensitive (QDI) asynchronous designs can simultaneously provide higher performance, lower energy consumption and less sensitivity to the process variations compared to their clocked counterparts. However, these circuits normally exhibit more silicon area overhead. A significant source of additional area are the staticizer (a.k.a. keeper) circuits used by state-holding gates, which occur frequently in QDI circuits. In this paper, a shared-staticizer solution is presented, to eliminate some part of this area overhead. Effectiveness of the proposed shared-staticizer method is evaluated in several technology nodes and different asynchronous designs. Results show this technique works correctly down to subthreshold voltage and is superior to standard staticizer implementations with respect to area consumption with no impact on performance or power.