I am a bit lost about how to establish the parameters to establish differential pair routing. I am currently trying to route several differential pair and I am a bit new to this. I have searched online some tutorial but I don't find any really explaining easily and out of the theory with simple succession of steps about how to do it
I have downloaded saturn PCB software to see if it can help but I don't understand well how the soft is working because what it ask me to input is typically what I am searching for (it looks it is reverted... !!!)
Assuming the differential pair I am routing is requiring 90 ohm (this is what the hardware guideline say "Route the USB differential pair on the top layer with a trace width and differential spacing tuned to the PCB stack-up for 90Ω differential impedance ").
So in Saturn PCB I have indicated in target zdiff : 90 Conductor spacing: I don't know (Am I supposed to arbitrary settle this, then accomodate the other parameters ?) Conductor width: same Conductor height: this I suppose I need to check my layer stack up. In this case I suppose I have to decide the spacing between top track and ??? first prepreg or core ?
I would really appreciate if someone who have experience could explain their methodology via a "1./ 2./ 3./ 4./ points methodology" to be able to achieve any differential pair routing.