Study of Different Adders Using Full Swing Gate Diffusion Input

Abstract

This paper presents the comparison of Multiple 16 Bit Adders using Gate Diffusion Input (GDI) and CMOS logic. Performance enhancements using Swing Restoration has been studied. The paper focuses on three commonly used adders: Ripple Carry Adder, Carry Select Adder and the Carry Lookahead Adder. The simulation results reveal smaller area and better consumption for the GDI logic when compared with their CMOS designs at 180nm GPDK Technologies. The results have been evaluated using spectre in Cadence Virtuoso IC614. For Ripple carry adder and carry Select adder the GDI logic out performs the CMOS logic in terms of area and power. However, CMOS shows better performance in terms of delay and Rise/Fall time. For Carry lookahead adder, GDI performs better in terms of area, while CMOS performs better in terms of power, delay and Rise/Fall Time.)