[SI-LIST] : Re: IBIS connector models

Dr. Edward P. Sayre (esayre@nesa.com)
Mon, 15 Dec 1997 13:41:21 -0500

John & others:

Do you do your measurements with connector mounted on a circuit card with
ground planes or is the connect probed at the connection points with 50
ohm probing? Using your differential measurement, how do you account for
signal/ground positions or ratios?

I favor mounting connectors on circuit cards to include the mounting and
footprint effects. I do not favor Maxwell matrices in IBIS unless they can
be measured and characterized. Many Maxwell matrices include as many as
30+ crossections with no real justification on circuit element grounds for
the large number. They often do not account for losses very well either.

Aside from that, Maxwell matrices are not theoretically what one measures
in a coupled N-port circuit measurement.

Ed Sayre

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