[Resistance Matrix] keyword

Hello Ibisians,

      I wonder if somebody could clarify the use of resistance matrices in
package models. Should the values entered in these matrices be in Siemens or
Ohms?

      It seems to me that the resistance matrix is really a conductance
matrix, because in the case of a banded matrix (for example) it is assumed
that values outside the bandwidth are zero - doesn't this mean zero Ohms and
so wouldn't it mean that the corresponding pins would be short circuited
togther? Zero conductance on the other hand would imply an open circuit
which would make more sense.

     For example if we had a 2 pin package:

[Resistance Matrix] Banded_matrix
[Bandwidth] 0
[Row] 1
1.0
[Row] 2
1.0

  My understanding of the IBIS spec' leads me to understand that the full
matrix would be:

        | 1 0 |
        | 0 1 |

I.e. pins 1 and 2 have resistances of 1 Ohm, but there is a 0 Ohm short
circuit between them.

Have I misunderstood something here?

I'm about to model a device package where there is a degree of resistive
coupling between the pins and I need to know the correct units to use,
Siemens or Ohms?
Haruny Said
H.A.S. Electronics, Inc.
130 Bishop Allen Drive
Cambridge MA 02139
Email haselect@haselect.com
WWW http://www.haselect.com

Phone (617) 868 7828
Received on Sun Apr 7 16:15:11 1996