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

Luke Kenneth Casson Leighton lkcl at lkcl.net
Fri Oct 6 19:19:08 BST 2017


On Tue, Oct 3, 2017 at 8:48 PM, Richard Wilbur <richard.wilbur at gmail.com> wrote:

>> the defaults in PADS for the gap separation btw were set to 2x.  4x
>> seems an _awful_ lot, to my eye: i don't believe i've ever seen
>> wiggles with such large separation.  are you sure the app note didn't
>> mean "4x separation centre-to-centre of the traces"?  or, was the app
>> note specifically applying to really *really* high frequency traces
>> (above say... 2 or even 3 ghz)?
>
> Toradex, p. 17, section 6.2 as illustrated in figure 13.
>
> It matters more the greater the length of facing copper.  So if you can only get 15mil separation but split it into two or more wiggles, that would be better than having one wiggle at 15mil separation (between facing copper of the same trace).

 ok understood.   sorry took a while to reply.

 ok so i think what i'll do is, turn HX1T into two wiggles (still with
20mil separation), there's space to do that, but otherwise leave
everything else alone.

 nearly there - i still have to reply to the message a few days ago
about the keepout area.

l.



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