Dynamic pass-transistor dot operators for efficient parallel-prefix adders

We employ a dynamic pass-transistor technique to drastically reduce the area requirement and power dissipation of the dot-operator cell in parallel-prefix adders. The technique is demonstrated in both 0.35 μm and 0.13 μm process technologies on a 64-bit Kogge-Stone carry tree. In a comparison with a corresponding domino implementation it is shown that the transistor count and the power dissipation can be reduced with as much as 25% and 50%, respectively. On top of the area and power reduction, the delay can also be significantly reduced by using NMOS precharge transistors, but this requires a clock signal with a higher voltage.