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Customize Serial Link Project for Pre-Layout Analysis

You can modify the schematic elements to customize your designs in the Serial Link Designer app.

Using I/O buffers

An I/O buffer is represented by a designator. You change the buffer model for a designator in three ways:

  • Edit Designator Part/Pins dialog box

    Right clicking on the designator and selecting Edit Designator Part/Pins opens the Edit Designator Part/Pins dialog box. The Designator parameter allows the designator name to be changed. The Part Name parameter lists the parts in all libraries. When a specific part is selected in the dropdown menu, the IBIS file name referenced by that part is shown in the IBIS File parameter. The IBIS component name for the selected part is shown in the IBIS Component parameter. The table on the left shows all of the pins in the IBIS component. To associate a pin or pins with the designator select the pin or pins on the left and click one of the arrow buttons between the two tables. The pins in the table on the left can be filtered using the Wildcard Filter parameter. To add a column that shows the name of the transfer net that uses the pins, select Generate Used Pin Information.

  • Select IBIS File & Model dialog box

    Right clicking on the designator and selecting Select IBIS Model and File opens the Select IBIS File & Model dialog box. You can select an IBIS file from the table provided, or import your own. You can also select one or more pins from the table of pins in the selected IBIS files.

  • Default model

    To assign a default model to a designator, right click on the designator and select Use Default Driver, Use Default Receiver or Use Default I/O.

Using Transmission Lines

The app uses two types of transmission lines:

  • Ideal transmission lines

    Ideal transmission line models have two parameters: Impedance (Z0) and delay (Tpd). These parameters are set from the Element Properties dialog box for ideal transmission lines. Double click on an ideal transmission line symbol on the schematic to launch the Element Properties dialog box. There are columns for Impedance and Delay/Distance and checkboxes to sweep the parameters. Checking a sweep checkbox creates a variable in the solution space for the parameter.

    The model on the schematic is the model for the typical etch corner. If other etch corners are simulated the Z0 and Tpd parameters are scaled according to the corner conditions specified in the Corner Conditions dialog box. See Specify Corner Conditions in Serial Link Design for more information.

  • Lossy transmission lines

  • The lossy transmission line have a frequency dependent RLGC model that is created by a 2-D field solver.

    The app has a field solver with a transmission line editor for entering a cross-section. The transmission line editor can be used to create models in the libraries or to edit the model for a symbol.

    To associate a model in the library with the transmission line, right click on the symbol and choose Select T-Line Model. You can edit the default model by right clicking on the symbol and choosing Edit T-Line Model.

Using Vias

You can create via models based on a stackup and via physical parameters. Via models can be single-ended or differential. The first time a via symbol is placed on a sheet the default stackup is created. A dialog launches to allow the number of signal layers in the default stackup to be specified. For more information, see Via and Stackup Management in Serial Link Project.

Using S-Parameters

S-Parameter files must be imported into the app before being used on a sheet. As connections are added the body of the S-Parameter symbol will be red if there are any unbalanced connections or unused ports. The app assumes unused ports are terminated by default. S-Parameters can be checked for consistency and correctness using the S-Parameter check feature. For more information, see Edit Imported S-Parameter Data.

See Also

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