User's Guide

BL28EU-RD1 OEM Manual and User Guide
7
Figure 6-3
Assume the main PCB above with a 6 layer stackup with ground cut away on layer 2 so the microstrip
lines reference ground on layer 3. The dielectric thickness from L1 to L3 is 21.2 mils.
Using an online impedance calculator, the line width under the NAD for a 50 ohm line is 16.9mils
(433micron) shown below:
BL
Figure 6-4
The calculation for the microstrip line width outside the NAD is 37.7mils (967micron) shown below: