Impedance calculator

In high frequency PCB designs the impedance of a signal leading medium needs to be recognized. So it is convenient to determine the later width of a track in the layout already in the schematic. This should be possible for single signals or for signal classes as well. It is about the principle of how a strip line should be constructed. (StripLine).

Image: StripLine (Cross section)

Open in TARGET 3001! the Impedance calculator either in the dialog Change signal wires (Double click on a signal wire or [e] after having highlighted the signal) or in the dialog Edit signal classes (menu actions).

Image: The dialog: "Signalbahnen ändern"

Image: The dialog: "Signal-Klassen verwalten"

The following terms are of interest:

• The hugeness h of the dielectric agens the StripLine is embedded to (= the body of the PCB)
• The copper thickness t of the StripLine
• The permittivity ε_r of the dielectric agens

A certain Nominal impedanz Z required, needs the required track width w according to the the facts given. It can be overtaken to the signal class as standard width.

If the StripLine is placed double (differential StripLine), the distance s between both tracks plays an additional role. The required spacing between the tracks is calculated and overtaken to the signal class definitions.

Image: The Impedance calculator suggests the best track width and overtakes the value to a signal or a signal class.