RXP/N and TXP/N pairs should be routed with controlled 90-Ω differential impedance (±15%).
Keep away from other high speed signals.
Intra-pair routing should be kept to within 2 mils.
Length matching should be near the location of mismatch
Each pair should be separated at least by 3 times the signal trace width.
The use of bends in differential traces should be kept to a minimum. When bends are used, the number of left and right bends should be as equal as possible and the angle of the bend should be ≥ 135 degrees. This minimizes any length mismatch causes by the bends; ad therefore, minimize the impact bends have on EMI.
Route all differential pairs on the same of layer.
The number of VIAS should be kept to a minimum. It is recommended to keep the VIAS count to 2 or less.
Keep traces on layers adjacent to ground plane.
Do NOT route differential pairs over any plane split.
Adding Test points causes impedance discontinuity; and therefore, negatively impact signal performance. If test points are used, they should be placed in series and symmetrically. They must not be placed in a manner that causes a stub on the differential pair.