Design and Analysis of 16-bit ALU using Gate Diffusion Input (GDI) Technique

This study presents a 16-bit Arithmetic Logic Unit (ALU) designed using the Gate Diffusion Input (GDI) technique, aimed at minimizing transistor count at the block level. As a core part of processors, the ALU performs essential arithmetic and logical functions for computing. By utilizing GDI, this ALU optimizes transistor efficiency, supporting operations such as addition, subtraction, AND, XOR, XNOR, NAND, OR, and NOT. A 1:8 demultiplexer was integrated to streamline input signal distribution, reducing hardware complexity. Compared to conventional CMOS designs, this GDI-based ALU demonstrates clear advantages in terms of lower transistor use, reduced power consumption, and minimized size. Design and simulation were performed using DSCH 3.5, showing improved energy efficiency and compactness, making it well-suited for low-power applications.