I'm about to lay out a USB 90 ohm diff pair, and I go to the eeweb impedance online calculator
I punch in my numbers from the fab house
Trace Thickness = 1.4 mil Substrate Height = 14.4 mil Trace Width = 6 mil Trace Spacing = 8 mil Dielectric = 4.5
and I get 89.9 Ohms
Then I try to verify against another impedance calculator, I pull up Saturn PCB Toolkit and plug in the same info
Conductor Width = 6 mil Conductor Spacing = 8 mil Conductor Height = 14.4 mil Base Copper Weight 1oz Dielectric 4.5
and I get 77 Ohms
Does anyone have a tool they like for these type of impedance calculations? I don't know why the solutions are are off, I suspect user error
These are for inner layers with a ground plane...
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