If you ever had to change impedance trace width when going to production keep reading…
Calculating trace width and spacing of impedance controlled traces is complicated enough.
It is one thing to own an expensive simulation tool that will handle these nasty Maxwell equations for you but it is another to also incorporate your FAB house lamination empirical data into the mix.
To keep simple try to stick to conventional Stack ups using Prepreg and core thickness that are commonly used by most PCB FAB houses. Then the only thing that can drive modification of your traces when going to production in the empirical data your FAB house has laminating a specific stack up. Once you locked in on a commonly used stack up these changes should be minimal.
Here are few examples that will spare you changes to routing after have released your gerbers for PCB Fabrication. More stack ups templates can be found on our website.
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