> -----Original Message-----
> From: piclist-bounces@mit.edu On Behalf Of Phil Keller
> Sent: Thursday, January 18, 2007 1:42 PM
> 
>   The reference I was using for via size is:
> http://www.ultracad.com/articles/viacurrents.pdf
> 
>   The fab house I use has a trace thickness of 1.3mil-2mil  (standard 
> 1oz/sqft) and  a via wall thickness of 0.8mil-1.2mil.
> 
> Phil

Since the via plating can be almost 1/2 the minimum trace thickness, I'd use
a factor of 2 for safety. So with 40mil selected for regular traces your
total calculation is (40mil/pi)*2 =~ 25.5. Then of course increase it for
extra safety.

Paul

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