Review on Custom and Semicustom Designs for Multibit Arithmetic Logic Units Using CMOS

Abstract

In this paper authors have presented an extensive review on literature on designing of multibit arithmetic logic units based on custom and semicustom techniques. A brief review is carried out for proposed design and will be done using MOSIS C5 process for VLSI. Arithmetic Logic Unit is a digital circuit that performs arithmetic and logical operations. ALU is a fundamental building block of central processing unit of a computer which is used in the simplest microprocessors for purpose of maintaining timers. Previously, many efficient architecture have been introduced for the design of low complexity operation, but we have given attention to custom designing of ALU, where every sub module is designed simulated and verified then routed accordingly. The proposed design of ALU will performs the mathematical, logical, and shifting operations like Addition, Subtraction, Multiplication, Increment, Decrement, Logical AND, Logical OR, Logical XOR etc. in the computer. In this paper, the efficient modules of ALU will be design using Custom Tools like Electric CAD and simulation results will be verified on same platform using test benches and SPICE simulations.