Re: [SI-LIST] : Formulas for Calculating PTH Capacitance

Mike Jenkins (jenkins@lsil.com)
Tue, 23 Sep 1997 10:10:23 -0700

Chris,

I strongly doubt there's an analytic formula for via capacitance,
but an upper bound that seems fairly tight is to assume a coaxial
structure where the outer diameter is the clearance diameter:

C = 2 * PI * eps * board thickness
------------------------------
ln( clearance dia / hole dia )

Otherwise there's always copper sheets and a tin can. ;)

Mike

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