Fast and High-Performing 1-Bit Full Adder Circuit Based on Input Switching Activity Patterns and Gate Diffusion Input Technique

For computational arithmetic, a full adder is the primary logic units in VLSI applications. A new full adder circuit design has been presented in this article which is based on input switching activity pattern and gate diffusion input (GDI) technique. The adder has been designed in two stages. The first stage is an XOR-XNOR module, whereas, the final stage is for the required outputs. By using the switching activity pattern of inputs and GDI techniques at each stage, the switching activities of the transistors have been minimized. This improves delay, power consumption and computational complexity. The adder has been designed and evaluated by using the synopsis tool and compared with different existing adder cells found in the literature. It is found that the presented adder shows an improvement at least 72.86% and 66.67% in terms of speed and energy consumption, respectively. Extensive performance analyses of the full adder have also been evaluated at 32 nm CMOS and 32 nm CNFET technology node which shows promising performances in both the technology nodes.