[Arm-netbook] EOMA68-A20 2.7.4 pre-production prototypes received and working

Luke Kenneth Casson Leighton lkcl at lkcl.net
Fri Jun 16 08:07:10 BST 2017

On Fri, Jun 16, 2017 at 8:03 AM, mike.valk at gmail.com
<mike.valk at gmail.com> wrote:

>> > . Cut the pads tight a little shorter and place the via's to the right
>> > creating a bottleneck but stil far enough from the edge
>>  possible.
>> > . The above but to the left, via's in the middle.
>>  possible but risky.
> Depends on how near to can get to left hand pads or the egde on the right
> and were the pads in the connector have most tolerance.
> Speaking of near the edge. The tracks on the board seem awfully close the
> boards cutoff edge.

 yyep they are.

> Doesn't that create a problem for cutting them out?

 no but it does cause an imbalance in the differential pairs unless
the tracks come in dead-straight from the left, and it also means that
ground shielding isn't possible.

 normally the connector would be at least 20-30 mil away from the edge
so that ground vias could be placed all along the right-hand edge.
that's near-flat-out impossible.  the best that can be hoped for is
that the three pins (in grey) which are GND will do the job of
creating an EMI shield instead.


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