[Arm-netbook] HDMI High-Frequency Layout: Recommendations--Taper

[Richard Wilbur]

On Dec 18, 2017, at 08:27, Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
> On Mon, Dec 18, 2017 at 2:55 PM, Richard Wilbur
> <richard.wilbur at gmail.com> wrote:
>> 
>> After sleeping on it, I'd recommend making the new, deeper ground fill
>> slightly larger (~5mil? margin) than the ground keepout on the
>> original reference plane--as long as that's not too hard to
>> accomplish.

In this case I was speaking of what I had quoted above this excerpt in its original context which was the treatment of traces beneath the ESD components (not the connector).  In fact the trace in the middle of each ESD component is ground and is connected to other ground layers by several vias.  Under that trace we might as well have a ribbon of ground plane on layers 2 and 5.

> um... um....  noo shouuuld be fiiine....   niggles: from the last
> picture you can see i have HHPD coming in at the top.  and also i
> remembered, pin 19 is 5V power, that's coming in (big track, green) on
> Layer 4.  however.... Layer 5 and 3 would have GND surround it, so
> that's ok.

Looks fine.  As long as the high-frequency pins of the connector land on layer 1 with an unobstructed view of the ground plane on layer 5, I think we will have achieved our goal (moving the ground plane deeper in order to try and maintain ~100Ω differential impedance).