--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Thu, Oct 12, 2017 at 7:30 PM, Richard Wilbur <[email protected]> wrote: > On Oct 11, 2017, at 18:08, Luke Kenneth Casson Leighton <[email protected]> wrote: >> On Wed, Oct 11, 2017 at 6:18 PM, Richard Wilbur >> <[email protected]> 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? > > I think you are probably correct here. I think the capacitance has to do > with length of trace near other copper (same layer or not) and separation > distance between the trace in question and the other copper. Also the area > of the trace and other copper which are facing each other. i honestly don't know if PADS is that sophisticated. the Lynx SI add-on (which is... tens of thousands of dollars) certainly will be. > Which layout are these measurements coming from? Is it pictured at a > publicly available URL? no change in a week. i'll always update the news page and send a message here indicating that i've done that. latest will always be here http://rhombus-tech.net/allwinner_a10/news/ - i will always add the latest image onto the end of the latest news. so at this time, right now, that will be http://rhombus-tech.net/allwinner_a10/news/eoma68-a20-275-hdmi-new-wiggles-layer6.jpg l. _______________________________________________ arm-netbook mailing list [email protected] http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to [email protected]
