On Tue, 11 Nov 1997, Brock Hunter wrote:

>Does anyone know the formula(s) for calculating the impedance of
>differential pairs when the lines are on adjacent layers to one another
>and NOT side by side on the same layer, or perhaps software that handles
>this type of configuration? This does not appear to be covered in
>IPC-D-275.
>
>Thanks in advance for any enlightenment.
>
>        Brock
>
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Brock,
   I have used a program that I got from an engineer way back that can give you
ball park values for differential impedance. Actually it's darn close. I could
send you a copy if you like. Let me know off line. The only thing you will need
to have handy when you use it is an engineer that understands odd and even mode.
I had some info on this myself but I loaned it to an ENGINEER and I need to get
it back.

Scott Decker
Senior PCB Designer

AKA: PadMasterson
E-Mail: [log in to unmask]

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