D = distance between two differential pair signals; W = width of a trace in a differential pair; S = distance between the trace in a differential pair; and H = dielectric height above the group plane.
Use the following guidelines when using two differential pairs:
■ Keep the distance between the differential traces (S) constant over
the entire trace length.
■ Ensure that D > 2S to minimize the crosstalk between the two
differential pairs.
■ Place the differential traces S = 3H as they leave the device to
minimize reflection noise.
■ Keep the length of the two differential traces the same to minimize
the skew and phase difference.
■ Avoid using multiple vias because they can cause impedance
mismatch and inductance