On Mon, Dec 18, 2017 at 6:03 AM, Richard Wilbur richard.wilbur@gmail.com wrote:
So it might be easier to just put a ground keepout on layer 2 under the ESD component on layer 1 and a corresponding ground fill on layer 3. Likewise a ground keepout on layer 5 under the ESD component(s) on layer 6 and a corresponding ground fill on layer 4.
yehyeh. ah.... do you mean the *whole* component? conflicts with putting keepout(s) under individual pads...
I was recommending just under the ESD pads specifically for the high-frequency differential signals.
conflicts with words above about "GND keepout under ESD components"...
Likewise with the connector, I would put a ground keep out under the lands on layer 2 (probably best to just draw a keepout under the whole connector on layer 2)
including for the HSCL, HHPD and even the GND pads? of course there's VIAs connecting the tracks in between the diff-pairs
Wouldn't have to I suppose but the idea is to move the ground further away from the high-frequency pads to reduce the capacitive coupling thus increasing the impedance. Thus I think it's probably best to extend the layer 2 keepout under the whole connector.
got it.
l.