Differential pairs must be routed with controlled 100-Ω differential impedance (± 20%) or 50-Ω single-ended impedance (±15%).
Keep away from other high speed signals
Keep lengths to within 5 mils of each other.
Length matching must be near the location of mismatch.
Each pair must be separated at least by 3 times the signal trace width.
The use of bends in differential traces must be kept to a minimum. When bends are used, the number of left and right bends must be as equal as possible and the angle of the bend must be ≥ 135 degrees. This arrangement minimizes any length mismatch caused by the bends and therefore minimizes the impact that bends have on EMI.
Route all differential pairs on the same of layer.
The number of vias must be kept to a minimum. It is recommended to keep the via 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 will cause impedance discontinuity and will therefore negatively impact signal performance. If test points are used, they must be placed in series and symmetrically. They must not be placed in a manner that causes a stub on the differential pair.