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

Luke Kenneth Casson Leighton lkcl at lkcl.net
Thu Oct 12 01:08:11 BST 2017

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On Wed, Oct 11, 2017 at 6:18 PM, Richard Wilbur
<richard.wilbur at gmail.com> wrote:
> Afterthought:  If PADS does give impedance values, please include the
> values for each of the HDMI differential traces and a URL to images of
> the top and bottom layers of that layout.

 they're all 89 ohms, single-line.

> That way I'll be able to make recommendations and markup the picture
> to hopefully make everything clear.

 appreciated... there's no differences: they're all 89 ohms.  i'm
assuming that's calculated from track width and board / layer widths.

 capacitance is slightly different: the shorter traces (TX2) are
3.06pF, the longer ones (CK) are 3.55pF - i would imagine that the
extra length results in a directly-proportionally larger capacitance?


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