USB D+/D- trace routing

[mg9]

Dear all, I would like to seek your opinion on the USB signal trace routing. I'm using FR1 silver ink thru hole 1.0mm PWB, and the routing of the trace is as the attachment. Is it necessary to put 2 vias (as the attach file) instead of 1 via? My concern is the via is silver ink thru, not plated like FR4 PWB. Conductivity/impedance may not as good as plated thru hole, FR1 via is using silver ink, and may not consistance all the way. Is there any study on the pros & cons of these 2 diff via for high speed data line? I worry it will affect the eye diagram...

For grounding trace, 2 via may create a loop, but for my case, is there any concern as well?

 

[poopeater]

Putting two vias like that will cause as much (if not more) of an impedance discontinuity as having a single via. Where is the reference plane for this trace?

I am not familiar with the silver ink thru technology. Why are you concerned with poor conductivity through the via?

Another question: Is this for USB 1.1 or 2.0? For 1.1 speeds, the via is a don't care. The signals aren't even fast enough to 'see' it. At 2.0 speeds, I really don't think you'd have an issue either, provided that you have a good return plane and a good, controlled impedance through the length of the trace leading up to the via.

 

[mg9]

Putting two vias like that will cause as much (if not more) of an impedance discontinuity as having a single via. Where is the reference plane for this trace?

I am not familiar with the silver ink thru technology. Why are you concerned with poor conductivity through the via?

Another question: Is this for USB 1.1 or 2.0? For 1.1 speeds, the via is a don't care. The signals aren't even fast enough to 'see' it. At 2.0 speeds, I really don't think you'd have an issue either, provided that you have a good return plane and a good, controlled impedance through the length of the trace leading up to the via.

Both D+ and D- line will run parallel to USB connector, and the gnd will be the reference plane, and i fill one side(i'm using double side PCB) with all the gnd as possible.

I just concern if the via would cause any impedance discontinuity and would affect the eye diagram? Although this is USB 1.1, but I need to make sure for future, USB 2.0 compliance is not an issue.

I will go for 1 via, and see if ok or not. Hope to get my PCB in 1wks time and test it. I do appreciate your comments here, thanks bro...

 

[poopeater]

Let us all know how it works out! You do have controlled impedance traces on the USB lines that are 85-100 ohms differential, right?