SI FD Analysis
In the figure above just pin IC100-C19 of net net7699 was shifted to the Excitations/ports frame by the user. The other net ADDR(5) was recognized by the program and the corresponding pins of the further components were entered automatically. In order to remove a certain pin (or group of pins), the pin has to be selected and shifted by using the left-direction arrow (or by dragging it with the mouse).
Pin: Displays the pin which was either shifted from the Available pins frame by the user or added automatically by the program. The field can not be edited. Note: For this kind of analysis the current return path is assumed as ideal. Therefore, a single pin is sufficient to generate a port, since the reference pin is assumed as the ideal ground reference.
Net: Displays the corresponding net of the corresponding pin. The field can not be edited.
Termination: Allows the user to add a termination network between the pin and the connected net on the PCB from a predefined list (see I/O Device Modeling). This functionality is useful if the user wants to perform a quick what-if analysis without having to change any layout in the first place.
Fmin: specifies the frequency where the analysis starts
Fmax: specifies he frequency where the analysis stops
Samples: number of frequency points to be calculated
Ref-Impedance: defines the reference impedance for the S-Parameter
Logarithmic sweep: defines whether the Samples are distributed linear over the given frequency range or logarithmic over each decade within the given frequency range.
The Meshing Settings frame includes the following four parameters (see also 2DTL Meshing tab):
Search distance for coupling: Parallel segments of different (but selected) nets were considered electromagnetically coupled within this distance (see Search distance for coupling).
Minimum length for coupling: Parallel segments must have a certain minimum length to be accepted for an electromagnetic coupling (see Minimum length for coupling).
Use legacy via model: Defines which kind of via model should be used. For more explanation, see Use legacy via model.
Consider padshapes: Defines whether pad shapes shall be considered or not. For more explanation, see Consider padshapes.
Consider meander interaction: Defines whether the electromagnetic coupling between segments belonging to the same net shall be considered or not, see Consider meander interaction
The Model Settings frame includes only one parameters (see also 2DTL Modeling tab):
Dielectric losses: Specifies whether dielectric losses shall be considered or not (see 2DTL Modeling tab, Dielectric loss modeling).
The Simulation Settings frame includes only one parameter:
Differential: Normally, the number of listed pins lead to an identical number of ports. In this case, every port consists of its corresponding pin and an ideal ground reference. If the Differential option is activated the generation of ports follows two distinct interpretation: The first interpretation is that the two pins on each end of the differential pair line build so called differential mode ports and the corresponding S-Parameter reflects the transmisssion through these differential ports. The second interpretation is that the two pins on each end of the differential pair line are shorted and so called common mode ports are built between the shorted pins and the ideal ground reference. Note: This function is only possible if there are exactly two pin pairs (see figure below):
The whole set of S-Parameter for the pure differential mode, the pure common mode and the conversion from differential to common mode can be calculated within one simulation task by using two mode converter blocks as shown in the figure below:
