On Fri, Aug 4, 2017 at 8:51 AM, mike.valk@gmail.com mike.valk@gmail.com wrote:
2017-08-04 9:19 GMT+02:00 Luke Kenneth Casson Leighton lkcl@lkcl.net:
On Thu, Aug 3, 2017 at 11:53 PM, Richard Wilbur richard.wilbur@gmail.com wrote:
- Instead of using two separate anti-pads on signal vias, combine
them into an oval shared antipad (on every layer) to reduce parasitic capacitance.
oo. never heard of this practice. never heard of "anti-pads" either! so sorry, if you put some references i missed them.
https://e2e.ti.com/cfs-file/__key/communityserver-blogs-components-weblogfil...
From https://e2e.ti.com/blogs_/b/analogwire/archive/2015/06/10/differential-pairs...
Basically a barrier between a via and a passing layer. Something default to prevent shorting.
oh, ok - just a hole where you'd expect one to be :) didn't know its name was "anti-pad".
With differentals have them combined so there is nothing in between them in a horizontal line/z axis as well.
turns out that the anti-pads from PADS are big enough to create a figure-8.
l.