A new design of low power high speed hybrid CMOS full adder

We have designed the full Adder using hybrid-CMOS logic style by dividing it in three modules so that it can be optimized at various levels. First module is an XOR-XNOR circuit, which generates full swing XOR and XNOR outputs simultaneously and have a good driving capability. It also consumes minimum power and provides better delay performance. Second module is a sum circuit which is also a XOR circuit and uses carry input and the output of the first module as input to generate sum output. Third module is a carry circuit which uses the output of the first stage and other inputs to generate carry output. In the new full adder design we have proposed new full adder circuit which reduce the power consumption, delay between carry out to carry in and PDP by 12 to 100%. Simulations are carried out on HSPICE using TSMC 0.18 μm CMOS technology.

I. Introduction

Full adder is a basic building block for various arithmetic circuits such as multipliers, compressors, comparators and so on. The power requirement and output delay of these circuits is greatly depending upon the power requirement and delay of the full adder circuits. So for designing the high performance arithmetic circuits, minimization of the power and delay of the full adder circuit is required.