Table of Contents
ISRN Electronics
Volume 2012 (2012), Article ID 253742, 9 pages
Research Article

Design of High-Speed Adders for Efficient Digital Design Blocks

Department of Electronics and Communication, People’s Education Society Institute of Technology, Karnataka Bangalore 560 085, India

Received 19 June 2012; Accepted 22 July 2012

Academic Editors: J. Solsona and Y. Takahashi

Copyright © 2012 Deepa Yagain et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The core of every microprocessor and digital signal processor is its data path. The heart of data-path and addressing units in turn are arithmetic units which include adders. Parallel-prefix adders offer a highly efficient solution to the binary addition problem and are well suited for VLSI implementations. This paper involves the design and comparison of high-speed, parallel-prefix adders such as Kogge-Stone, Brent-Kung, Sklansky, and Kogge-Stone Ling adders. It is found that Kogge-Stone Ling adder performs much efficiently when compared to the other adders. Here, Kogge-Stone Ling adders and ripple adders are incorporated as a part of a lattice filter in order to prove their functionalities. It is seen that the operating frequency of lattice filter increases if parallel prefix Kogge-Stone Ling adder is used instead of ripple adders since the combinational delay of Kogge-Stone Ling adder is less. Further, design and comparison of different tree adder structures are performed using both CMOS logic and transmission gate logic. Using these adders, unsigned and signed comparators are designed as an application example and compared with their performance parameters such as area, delay, and power consumed. The design and simulations are done using 65 nm CMOS design library.