Our S-parameters are provided in a single compressed "zipped" file. The file must be "unzipped" after downloading to obtain the separate inductor value S-parameter files.
To model our chip inductors, either select the CCIND element from the Lumped Element - Inductor menu or place each individual lumped element for the model onto the schematic. An example chip inductor schematic is shown in Figure 1.
To model our power inductors, each individual lumped element (LVAR, C, R2, R1, RVAR1, RVAR2) for the complete model must be placed into the schematic. An example of a power inductor schematic is shown in Figure 2.
After all the lumped elements are placed into the schematic, change the value for each element to match the value in the model table for the specific inductor. If you plan to model different Coilcraft inductors in the same schematic, be sure to rename the individual lumped elements and variables, then update the values from the model table for each inductor.
Important! Our models represent de-embedded measurements in which fixture parasitic reactances have been removed. Fixture (or circuit board) parasitic reactances raise the effective impedance (and the effective inductance), lower the self-resonant frequency (SRF), and shift the Q curve. For the most accurate model of our inductors in your specific circuit environment, you must include your circuit board model in the simulation.
To view the effective series inductance of the model in a graph:
Q values and curves in our data sheets are typically based on measurements using an impedance analyzer in a 50 Ohm environment, giving a 1-port (reflection) measurement result. If Q calculations are to be compared with data sheet values and curves, they should be based on a simulation with one port of the inductor model connected to ground (as shown in Figure 2).
If you are interested in the Q of the inductor in a 2-port series configuration, the additional 50 Ohms impedance of the second port results in a lower simulated Q value than the 1-port configuration. This result is logical considering that the additional 50 Ohms applies to the "Re [Z]" in the denominator of the Q calculation equation.Q = Im [Z] / Re [Z]
At this time, Microwave Office does not have a Q measurement function. You must enter the equation for Q in the "Output Equations" window.