Re: [SI-LIST] : Trace impedance

Charles Bishop (bishop@ICD.Teradyne.COM)
Fri, 21 Aug 1998 07:28:38 -0400 (EDT)

This is an excellent point. In work that I've done, many of the
discrepancies were due to a failure to include allowances for
soldermask, actual etched trace width, and the resulting
trapazoidal trace cross-section.

Charlie Bishop
Teradyne Inc

>
> I believe there are some conformal mapping equations that actually take
> conductor thickness into account.
>
> Has anybody considered that the discrepancy between the calculation and
> measurement can actuall be due to poor measurements? I am not necessarily
> talk about impedance measurements (although, that too), but measurements
> and variations of board thickness and trace width, thickness etc.?
>
> Thanks,
>
> -Dima Smolyansky
>
>

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