I am confused about the correct PCB stack-up for 100 Ohm differential trace impedance.
Can you describe me the basic rules for this and advise relevant links?
For example, I have differential stripline signals, which should be 100 Ohm impedance.
Dielectric thickness may vary, but at the moment I have 4mils.
Trace thickness is 0.6mils.
So I need to choose the correct trace width/spacing, am I right?
Previously I was used 5mils width and 6mils spacing differential traces.
But when I put all these values to some calculator it gives me only 72 Ohm of differential impedance.
What could be wrong and what should I change in my values in order to have about 100 Ohm impedance?
Should I trust to such kind of calculators?
Thank you in advance!