Route RXP/N and TXP/N pairs with controlled 90Ω
differential impedance (±15%).
Keep away from other high speed signals.
Keep intra-pair routing to within 2 mils.
Place length matching near the location of
mismatch.
Separate each pair by at least 3 times the signal
trace width.
Keep the use of bends in differential traces to a
minimum. When bends are used, make sure to keep the number of left and right bends as
equal as possible and the angle of the bend ≥ 135 degrees. This minimizes any length
mismatch causes by the bends and therefore minimizes the impact bends have on EMI.
Route all differential pairs on the same of layer.
Keep the number of vias to a minimum. TI
recommends 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.
Note that adding test points can cause impedance
discontinuity, and therefore, negatively impact signal performance. If test
points are used, place the points in series and symmetrically. The points must
not be placed in a manner that causes a stub on the differential pair.