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Method to Compress Data for RC Delay Calculation

IP.com Disclosure Number: IPCOM000120447D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 62K

Publishing Venue

IBM

Related People

Abato, RP: AUTHOR [+2]

Abstract

By combining resistance (R) and capacitance (C) data for serially connected wire segments, volume of data required for calculating RC delays of wired networks is significantly reduced. Any of several existing algorithms may be used to calculate delays using this compressed data.

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Method to Compress Data for RC Delay Calculation

      By combining resistance (R) and capacitance (C) data for
serially connected wire segments, volume of data required for
calculating RC delays of wired networks is significantly reduced.
Any of several existing algorithms may be used to calculate delays
using this compressed data.

      This method reduces the number of wire segments for which R and
C information must be provided to an RC delay algorithm.  By
calculating total segment resistance, capacitance, and a distribution
factor (d) indicating how much of the distributed capacitance should
be associated with each end of the wire segment, lumped models of
wire segments having distributed R and C are created.  Then, serially
connected wire segments are combined into single, virtual segments
for use in an RC delay algorithn.  Serially connected segments are
those sharing a common node as an endpoint.  The common node must not
be shared by a circuit pin connected by a network or by any other
circuit segment. By repeating this process, a chain of serially
connected wire segments are compressed into a single, virtual
segment. The number of segments may always be compressed to less than
twice the number of pins which a network connects.

      Using a standard model of a wire having an infinite chain of
resistances and capacitances to create a lumped model, it is found
that half of the distributed capacitance should be modeled at each of
its ends.  Thus,...