High Speed PCB Layout: USB 3.0 Tracks On Top Layer or Stripline inc Vias??

[Chendy]

Hello,

I'm new to high-speed layout. Have been doing my best to learn.

What's the general recommendation when routing say a USB 3.0 signal between two SMD pads?

A) Route signal on the top layer, so no via transitions. But is microstrip so only shielded from below.
- I guess, this has better signal integrity but worse EMI/EMC susceptibility.
B) Route signal on an internal layer, 2x via transitions. But now stripline, so the signal is shielded by ground planes above and below.
- I guess this has worse signal integrity, but better EMI/EMC susceptibility

I have a network-router-type project.
I'm unsure what option would be better? Generally or perhaps for my use case.
I don't think we would have any unusual noise sources, this is a general consumer product.

Thanks : )

[eb4fbz]

I guess it depends on the required trace length. I would not bother going stripline for 10mm, but probably yes for >50mm.

[T3sl4co1l]

Worse with respect to what?

Microstrip with full-board ground plane is generally sufficient for commercial EMC levels.  Do you have more stringent levels to meet? A tight layout e.g. putting lines too close to the edge, or near slots, unrelated traces?

Tim

[Chendy]

@T3sl4co1l
"Worse with respect to what?"
Not sure, all things included I guess? Wanted to understand the general balance for my general use case as described.
Your answer is pretty much the sort of guidance I was looking for... No its a lowish density board without any special considerations

@eb4fbz
Thanks, helpful

[jonpaul]

See Howard Johnsons excellent site

https://highspeeddigitaldesign.com/hj.html

High Speed Digital Design: A Handbook of Black Magic
by Howard Johnson 

https://www.amazon.com/High-Speed-Digital-Design-Handbook/dp/0133957241

Enjoy and Bon Chance! '
Jon



Jon