Re: l impedance vs common mode impedance

Slav wrote:

> Dear community,
> can someone explain to me some misunderstandings. There is a differencial
> pair in a PCB. Simulation returns: Impedance 65.5 ohm, differencial
> impedance 98 ohm, common mode impedance 82 ohm..I wonder what is the
> difference between 'impedance' and 'common mode impedance'? Just
> 'impedance is (as I see it) the impedance of a trace, if that trace was
> alone.Well.But what common mode impedance is? Any links or tips would be
> appreciated. Slav.

This should be explained in the manual of your simulator. In case it is not,
ask google: Searching for "common mode impedance" gives as hit no. 12
http://www.ultracad.com/articles/diff_z.pdf, which should get you started.


Georg

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