If you allow "tangency" of drilled hole wall to signal pad feature, then
the antipad on a plane layer must be "signal pad + 2(.0085") - that means
the drilled hole if in spec (no breakout) will always be .0085" min. from
the copper plane. If you require 0.001" of annular ring, then you can make
the antipad "(signal pad - 0.001" + 2(.0085"). ....

NPTHs just need to have .0085"  annular ring "copper keep out zone" ..

Valerie




mattyk <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
02/03/2006 10:54 AM
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Re: [TN] In layman's terms, please?

That means no copper feature less than 8.5mils from edge of drill hole

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Genny Gibbard
Sent: Friday, February 03, 2006 10:52 AM
To: [log in to unmask]
Subject: [TN] In layman's terms, please?

What does "minimum drill to metal spacing less than 8.5mils is not
allowed" mean?

We must respond to a customer that our design meets this.

Thank you once again for sharing your wisdom...


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