[Arm-netbook] HDMI High-Frequency Layout: Impedance

[mike.valk at gmail.com]

2017-08-04 9:19 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:
> On Thu, Aug 3, 2017 at 11:53 PM, Richard Wilbur
> <richard.wilbur at gmail.com> wrote:
>
>> 3.  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-weblogfiles/00-00-00-03-25/3124.Fig1.jpg

From
https://e2e.ti.com/blogs_/b/analogwire/archive/2015/06/10/differential-pairs-four-things-you-need-to-know-about-vias

Basically a barrier between a via and a passing layer. Something
default to prevent shorting.

With differentals have them combined so there is nothing in between
them in a horizontal line/z axis as well.