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

Luke Kenneth Casson Leighton lkcl at lkcl.net
Sun Oct 22 20:12:06 BST 2017

crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

On Sun, Oct 22, 2017 at 7:33 PM, Richard Wilbur
<richard.wilbur at gmail.com> wrote:
> I'll try to get some computer time today and markup a picture
> with some ideas for the taper and geometry towards the connector end
> and send it to the list.

 thx richard.

> By the way, the Analog Devices employee's recommendations can't be exactly
> normative with my understanding of transmission line impedances--
> differential impedance < 2 * single-ended impedance.
> (In other words you'll want single-ended > 50Ω if you hope to get differential = 100Ω.)

 that makes a kind of sense

> I'd consider them design guidelines or goals in order to try and
>  keep the process from going in the ditch.

 well...  in theory it might be possible to change the layer stack
slightly (move layer 5 a bit further away from layer 1), or go to 4mil
track widths (but preferably *without* moving any of the traces!)

 the layer stack height alteration is an easy one to do.

 track width changes... yyeah... 4 mil would be the thinnest tracks on
the entire board, i'm reluctant to do it but we can do it if


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