KB: Extract impedance of routed copper traces
Created: July 13, 2023 | Updated: March 08, 2024
Altium Designer
Starting in version: 22
Up to Current
Piecewise ohmic DC resistance of each copper track/arc/via primitive is calculated using IPC2221 formula starting in AD22.8, while capacitance/inductance can be computed by setting up impedance profile(s) in Layer Stack Manager.
Solution Details
For a piecewise ohmic DC resistance of each track segment, the IPC2221 formula calculator has been implemented starting in AD22.8 as described here:https://www.altium.com/documentation/altium-designer/new?version=22#!key_highlights_22_8:~:text=Settings%20dialog.-,Added,-Max%20Current%20and
For a more elaborate numeric analysis leveraging field solver, please consider Power Analyzer .
For the capacitance referenced to the ground (intentional), there is a field solver integrated that you can leverage when you setup Impedance profile in Layer Stack Manager (Design » Layer Stack Manager from the top menu).
For the mutual capacitance to the neighboring conductors other than the the reference ground (unintentional), where you want to assess the influence of some co-planer conductor nearby, you can go through the similar workflow of setting up the impedance profile, but of two transmission variations, with and without co-planer configuration and comparing the result against each other.
Please refer below for further details:
https://resources.altium.com/p/parasitic-extraction-electromagnetic-solver-pcb-routing
https://resources.altium.com/sites/default/files/2020-03/Impedance%20Calculation_fin2.pdf
More general reference on impedance vs resistance:
https://resources.altium.com/p/when-trace-resistance-trumps-trace-impedance