Doug,
        Something to keep in mind here: Impedance (sort of the AC equivalent
of resistance) is defined as the square root of inductance divided by
capacitance. Mathematically, what that says is that as the capacitance goes
up the impedance goes down.
        Power/ground plane sandwiches act like big capacitors. As the
dielectric spacing goes down (the planes get closer together), the
capacitance goes up. That reduces the effective impedance of the planes.

-MH

> ----------
> From:         Doug M[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Doug M
> Sent:         Wednesday, March 07, 2001 2:52 PM
> To:   [log in to unmask]
> Subject:      [TN] Current on Copper Planes
>
> Where can I find an up to date on-line reference for
> the current carrying capacity of different weight
> copper planes (not traces)..
>
> Thanks
>

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