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 StripLine should be constructed. StripLine.

Image: StripLine (Cross section). The StripLine is the copper in the center.

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

Image: The dialog: "Change signal wires"

Image: The dialog: "Edit signal classes"

The following terms are of interest:

• The hugeness (height) 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 impedance Z required, needs the required track width w according to the the facts given. It can be overtaken to the signal or 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 as well.

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