Skip to main content
SpringerLink
Log in

A new design for a lookahead carry generator

  • Published:
Journal of VLSI signal processing systems for signal, image and video technology Aims and scope Submit manuscript

Abstract

We propose a new scheme for the Texas Instruments SN54182/SN74182 lookahead-carry generator. The SN54182/SN74182 provides a redundant carry output,C n+x . Our redesign provides an alternative to the original design that improves the performance of adder implementations. We analyze gate delays of lookahead adders with sizes of 16, 32, and 64 bits. We examine both CMOS-ASIC vendor technology and standard TTL implementations. In all cases, gate delays of sum and carry bits are improved. We also include a layout of our new lookahead-carry generator.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. J.Y. Cheung and J.G. Bredeson,Modern Digital Systems Design, West Publishing Company, pp. 160–164, 1990.

  2. P.K. Chan, M.D.F. Schlag, C.D. Thomborson, and V.G. Oklobdzija, “Delay optimization of carry-skip adders and block carry-lookahead adders,”Proceedings of the 10th IEEE Symposium on Computer Arithmetic, Piscataway, NJ, USA, pp. 154–164.

  3. Z. Hu, “Variants of an improvedm-valued carry look-ahead adder,”International Journal of Electronics, Vol. 71, pp. 799–803, 1991.

    Article  Google Scholar 

  4. B.D. Lee and V.G. Oklobdzija, “Optimization and speed improvement analysis of carry-lookahead adder structure,”Twenty-fourth Asilomar Conference on Signals, Systems and Computers, Vol. 2, pp. 918–922.

  5. Texas Instruments ALS/AS Logic Data Book, Texas Instruments Inc., 1986.

  6. National Semiconductor FAST Advanced Schottky TTL Logic Databook, National Semiconductor Corporation, 1990.

  7. Motorola CMOS Logic Data Book, Motorola Inc., 1991.

  8. 0.7-Micron Array-Based Products Databook, LSI Logic Corporation, Jan. 1993.

Download references

Author information

Authors and Affiliations

  1. Trimble Navigation, 2105 Donley Drive, 78758, Austin, TX

    Hercule Kwan & Robert Leonard Nelson Jr.

  2. Department of Electrical and Computer Engineering, University of Texas at Austin, 78712, Austin, TX

    Earl E. Swartzlander Jr.

Authors
  1. Hercule Kwan
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Robert Leonard Nelson Jr.
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Earl E. Swartzlander Jr.
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

This is a revised version of a paper that appeared in the Proceedings of the Twenty-Eighth Asilomar Conference on Signals, Systems and Computers, Vol. 2, pp. 1393–1397, 1994.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Kwan, H., Nelson, R.L. & Swartzlander, E.E. A new design for a lookahead carry generator. J VLSI Sign Process Syst Sign Image Video Technol 14, 295–302 (1996). https://doi.org/10.1007/BF00929622

Download citation

  • Received:

  • Revised:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00929622

Keywords

Search

Navigation