Design and Comparative Analysis of Half and Full Adders Using CMOS and Pass Transistor Logic Styles

Also Available Domains Nano Technology|Transistor Logic

Project Code :TVMABE360

Objective

The objective of this project is to design half and full adder circuits using CMOS and Pass Transistor Logic (PTL) styles and perform a comparative analysis of their performance. It focuses on evaluating key parameters such as propagation delay, power consumption, transistor count, and circuit area for both logic styles. The designs will be simulated and verified to ensure functional correctness and to accurately measure performance metrics. Comparative analysis will highlight the advantages and trade-offs of CMOS and PTL implementations in arithmetic circuit design. The overall goal is to identify the most efficient and reliable adder design suitable for high-performance digital applications.

Abstract

Abstract:

Energy-efficient designs are becoming more and more necessary as digital systems develop, particularly in applications with limited power, such as embedded and mobile systems. CMOS circuits still experience power losses during switching transitions, despite their widespread use due to their efficiency. To maximize energy usage, alternative logic designs including CMOS NAND gates, CMOS transmission gates, and NMOS pass transistor logic are investigated. The primary objective of this project is to design and test low-power, space-efficient half-adder and full-adder circuits using these three logic types. The designs are implemented and simulated to analyze key performance specifications namely transistor count, propagation latency, and utilization of power. The comparative analysis offers a means to optimize digital circuits for practical low-power applications by shedding light on how various logic types might be used in contemporary VLSI design.

NOTE: Without the concern of our team, please don't submit to the college. This Abstract varies based on student requirements.

Specifications

· Tool Used: Cadence EDA tools for schematic and simulation

· Technology Node:180nm CMOS process.

· Design Elements: complementary compound push–pull pair (PMOS + NMOS), input matching network, L1 & L2 (0.5 pH–10 pH) inductors, high-value output load (RL, 100 kΩ–1 MΩ), biasing/level-shift network, feedback/compensation path, input/output coupling and decoupling capacitors, thermal-stabilization circuitry, and symmetric/layout considerations for reduced mismatch

· Optimization Goal: minimize circuit complexity and parasitics (transistor and passive count) while preserving ultra-wideband large-signal gain, low output noise, high temperature stability, and linearity across the desired cutoff range (e.g., maintain cutoff from ≈18.21 kHz up to hundreds of GHz in simulation) with low power consumption (~69 mW)v

Learning Outcomes

Through the design and comparative analysis of half and full adders using CMOS and Pass Transistor Logic (PTL) styles, this project enables a thorough understanding of fundamental arithmetic circuit design in VLSI systems. Learners gain practical knowledge of implementing adder circuits using different logic styles and analyzing their impact on key performance parameters such as power consumption, propagation delay, transistor count, and area. The project enhances the ability to evaluate trade-offs between conventional CMOS logic and PTL in terms of power efficiency and speed, while also improving skills in circuit simulation, waveform analysis, and result interpretation using EDA tools. Overall, the project strengthens foundational concepts in low-power digital design and prepares learners to select suitable logic styles for energy-efficient arithmetic circuits in modern integrated systems.