Hi, I am going to use TUSB522p in the FPCB connecting between main board and USB Device.
Then I thought USB SSTX, SSRX lines should be on the top or bottom of layer as written in datasheet's guideline,
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but, our cad team said to meet 90 ohm impedance lines, then SSTX, SSRX lines should be 2nd or 3rd layer of the pcb.
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If I route these SSTX, SSRX in the 2nd or 3rd layer, then I should use several vias which will violate TI's layout guide line.
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Below is layout guide of TI's.
What is the best way in this situation?
1. Impedance 90 ohm is more important? -> Then SSTX, SSRX will routed in 2nd or 3rd layer and use several vias.
2. High Speed lines should be Top or bottom routed.-> Then SSTX, SSRX can not meet 90 ohm impedance.