Calculating differential impedance is similar in technique to that for the single-ended models, but with the addition of trace separation or offset. For some models the dielectric constant of the separation region can be specified separately from the substrate dielectric constant bulk value.
Enter the parameter values and tolerances if required into their respective fields and Click Calculate; the Si9000 calculates the resulting impedance. Use the other Calculate buttons to goal seek for the parameter values required to return a target impedance.