Electrical – USB 2.0 data lines swap suggestion

high speedroutingusb

I need your advice regarding the USB 2.0 signals routing. When I reach the USB connectors, the data lines (D+ and D-) have to be swapped. I have two options there: 1) swap the lines using vias and go from top to bottom layer for a short, 2) make a loop around the connector, like in the following picture.USB data lines routing

What is your suggestion, what is better option in therms of signal integrity ? I just wonder if this loop emphasizes antenna effect, but maybe the option with vias is worse.

P.S. Just to avoid confusion,bellow the top layer, there is a solid GND plane, so this split plane is power plane (layer 3), not the GND plane.

Thank you for your time,
Igor

Best Answer

For 480MHz (HS) USB, you need to length match the traces to within 150mils, but otherwise going the long way around is fine.

It's hard to tell what the amber area is, but you should avoid crossing planes if possible.

The full layout guideline for USB 2.0 is here: http://www.usb.org/developers/docs/hs_usb_pdg_r1_0.pdf