4 Layers impedance design

100 ohm differential impedance recommended design

line width, spacing 5/7/5mil differential pair and the distance between the pair ≥ 14mil (3W criterion);

Note: It is recommended that the entire group of differential signal lines is shielded with ground, and the distance between the differential signal and the shielded ground line is ≥35mil (in special cases, it cannot be less than 20mil).

90 ohm differential impedance recommended design

line width, spacing 6/6/6mil differential pair, and the distance between the pair ≥12mil (3W criterion).

Note: In the case of a long differential pair trace, it is recommended that the USB differential line wrap the ground at a distance of 6 mils on both sides to reduce the risk of EMI (with and without ground, the line width and line spacing standards are consistent).

Calculation parameters:

FR-4, thickness 1.6mm+/-10%, dielectric constant 4.4+/-0.2, copper thickness 1.0 oz (1.4mil), copper clad substrate(PP) 2116 (4.0-5.0mil), dielectric constant 4.3+/-0.2, solder mask thickness 0.6±0.2mil, dielectric constant 3.5+/-0.3.

Stack-up: