Delay uncertainty due to supply variations in static and dynamic full adders

In this paper, the delay uncertainty due to supply variations is investigated for two important full adder topologies. In particular, it is developed an analytical model of the delay sensitivity to supply variations for the static mirror adder and the dynamic dual-rail domino adder. The model is general and very simple, and allows for identifying the main parameters which define the delay uncertainty due to supply variations, as well as deriving design considerations. In particular, the importance of the input rise/fall time variations is clarified, and the effect of the supply voltage reduction and technology scaling is discussed. Results are validated through SPICE simulations with a 0.18-mum and a 0.35-mum technology