Browse Prior Art Database

Dynamic Crosstalk Control During Wire Routing

IP.com Disclosure Number: IPCOM000102676D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Linsker, R: AUTHOR

Abstract

Disclosed is a modification to a wire routing method that has the effect of reducing the number of connections whose electrical crosstalk coupling exceeds an allowed threshold.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Dynamic Crosstalk Control During Wire Routing

       Disclosed is a modification to a wire routing method that
has the effect of reducing the number of connections whose electrical
crosstalk coupling exceeds an allowed threshold.

      In the field of interconnection routing methods in which a wire
or connection is routed by computing a path of minimum cost (or
objective function value) between given termini, the disclosed
improvement consists of assigning a cost term to each site x through
which the wire passes, this term being of the form a(L)g(x), where
g(x) is a function of the number and type of connections occupying
the sites adjacent or in the neighborhood of x, and a(L) is a
function of the estimated length of the wire being routed.

      In a preferred embodiment, in which the distance for which one
net runs adjacent to another tends to be less than the crosstalk
saturation length, g(x) is chosen so as to be a measure of the
crosstalk per unit length coupled into a quiet line (the wire being
routed) at x by the active lines in its vicinity.

      A design goal is that the total crosstalk noise coupled into
each net be less than some allowed value.  If no control over
crosstalk is exercised, the longer connections will tend to
experience greater crosstalk.  The purpose of the improvement is to
provide a routing that tends to isolate the longer nets from other
nets; that is, a routing in which a longer net has less crosstalk per
unit length coupling into it.  This is accomplished by routing the
net using a cost function whose adjacency penalty term has a
coefficient a(L) that increa...