2017-08-17 18:30 GMT+02:00 Richard Wilbur <richard.wil...@gmail.com>: > On Aug 16, 2017, at 23:28, "mike.v...@gmail.com" <mike.v...@gmail.com> wrote: >> >> 2017-08-17 1:01 GMT+02:00 Richard Wilbur <richard.wil...@gmail.com>: >>>> On Aug 15, 2017, at 23:31, Luke Kenneth Casson Leighton <l...@lkcl.net> >>>> wrote: >>>> if i just take *out* the ground intermediary traces that would do the >>>> trick of bringing the impedance back up, is that right? >>> >>> Should be a major step in the right direction.
After thinking it through I have to agree. Each GND trace would become coupled with the diff pairs. Effectively creating a link between two pairs. Which we do not want. >>> >> >> How about the ground plane below the traces... That's a major stray >> capacitance and closer than the "narrow" surrounding GND traces? > > The ground plane would be stray except we designed it into the single-ended > and differential impedance. At this point it is integral to our differential > microstrip geometry. (See my original post in the thread "HDMI > High-Frequency Layout: Impedance".) I'll read that again. I guess we just need to make sure that no other GND loop crosses the HDMI plane. Perhaps create a barrier on the GND that follows the outer HDMI traces. To prevent unwanted GND loops http://www.ti.com/lit/ml/slyp173/slyp173.pdf _______________________________________________ arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netb...@files.phcomp.co.uk
