What is reference impedance?

What is reference impedance?

Reference impedance is a number that is used to define S parameters. If you have S parameters and you want information about voltages and currents (or vice versa), you need the reference impedance.

What is a PCB stackup?

A stackup is the arrangement of layers of copper and insulators that make up a PCB before designing the final layout of the board. good PCB stacking can also contribute to efficient and low-cost final production; a correct stack of PCB layers can improve the electromagnetic compatibility of the project.

Do you need a differential impedance calculator?

Working with many differential impedance calculators requires that you know the dielectric constant of the trace beforehand. This requires another impedance calculator tailored to your specific geometry, or you’ll need to manually work out the dielectric constant at each frequency in your PCB substrate.

How to calculate single ended impedance on a PCB?

In case you need to calculate single ended or differential pair impedance on your PCB, try following links: This link also has a track maximum current calculator , crosstalk calculator and thermal via calculator.

When does differential pair impedance matter in transmission?

Just like single-ended impedance, differential pair impedance matters when the trace behaves as a differential transmission line, which then depends on the transmission delay over a given trace. In the case where the signal rise time is very short, then the differential pair impedance should be matched to the source and load components.

How is the differential impedance of a microstrip trace determined?

The substrate dielectric and geometry determine the effective dielectric constant seen by signals on a microstrip trace, which also modifies the critical delay time and determines whether the single-ended trace acts as a transmission line. Coupling in a differential pair, which determines the differential impedance.