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Data Mining with Signal Integrity Viewer

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This example shows how to view, extract, and manage the simulation data from serial link projects using the Signal Integrity Viewer app. You can mine and manage data from the Signal Integrity Viewer app window or using the Table Column Control dialog box. For more information on the specific functions related to data mining, see Managing Simulation Data and Results. This example uses a serial link project, but the same principles apply to parallel link projects as well.

Open Example Project

Open the sldDataMiningExample project in the Serial Link Designer app.

openSignalIntegrityKit('sldDataMiningExample');

The project contains a single sheet, single channel design where the signals propagate from the transmitter to receiver through a transmitter package model, a differential via, a lossy transmission line, a second differential via, and a receiver package. The data stream is recovered at the receiver.

project.png

The schematic sheet is set up to simulate cases where the app sweeps the channel over the integrated circuit (IC) corner process (SS, FF, and TT) along with etch impedance and delay variations of +/-10% from nominal. The app sweeps the length of the transmission line from 4 to 12 inches. The app also sweeps three different via models. Each via model transitions between two layers. The VIA_TOP_BOT transitions from the top layer to the bottom layer of the printed circuit board. The VIA_TOP_SIG3_B transitions from the top layer to signal layer 3 with the barrel of the via from layer 4 to bottom being back drilled or removed. The VIA_TOP_SIG3_S transitions from the top layer to signal layer 3 also, however the barrel from layers 4 to bottom is not back drilled and leaves a large stub. This stub can cause reflections and signal quality issues resonances and/or impedance mismatches. There are a total of 81 simulations as a result for this set of variables.

By observing the simulation data, you can gain insight into the optimal via design for the channel.

Data Mining from Signal Integrity Viewer Window

Run the simulation to perform the statistical analysis.

After the simulations finishes and the Signal Integrity Viewer loads the results:

  1. Select the Statistical tab in the lower left corner of the viewer window.

  2. Open the Table Column Control dialog box by selecting the gear icon in the Row column header.

  3. In the Visible column, right click next to any of the check boxes and select Set All Invisible. This unchecks all columns and prevents them from being seen in the viewer.

  4. Select the check boxes for columns Stat Eye Height , $W1:LENGTH, $X_VIADIFF:V_MODEL, and CORNER and move them to the top using the arrows in the upper right of the dialog window.

  5. In the Stat Eye Height (V) column, filter any values greater than 100 mV by entering 0.1 in the wildcard filter box and setting the filtering option to Greater Than.

  6. Select the rollup on the $LENGTH column and set the Rolled Up Treatment in the Stat Eye Height to Min, Max. This allows you to see the minimum and maximum statistical eye heights for each of the corresponding lengths.

Rolling up on $LENGTH, while filtering on Stat Eye Height reveals that some lengths (12 inches) only have one simulation that meet the eye height requirement of greater that 0.1V. The other is how the some lengths (9 inches) have higher minimum and maximum than some shorter lengths. This is most likely due to the via model variable.

To investigate further:

  1. Filter the $X_VIADIFF:V_MODEL by putting VIA_TOP_SIG3_B in the wildcard box.

  2. Set the Stat Eye Height rollup treatment to Min, Max.

From this view you can see that using the VIA_TOP_SIG3_B (backdrilled via) in the design, over corner process and various channel lengths, meets the Stat Eye Height requirement of 0.1V in only one case (the 4 inch length). You can continue this flow and look at the results for simulations with the other via models in the design. Or you can relax the Stat Eye Height requirement to 0.05V and see which cases meet the criteria.

Data Mining with the Table Column Control

You can save and re-use the views that are set up in the Table Column Control after simulations have been re-run. You can also use the saved views with other projects.

Once you make a change to Table Column Control dialog box. the Selected Table View will change from Default to Modified. To save the view, click the View Manager button. This opens the Manage Table Views dialog box. The dialog box also shows any currently saved views.

When saving the current view, you have two options: User and Interface. The User option corresponds to the user (you) and is saved in the user’s local install area. It is available to you during the present and any subsequent Signal Integrity Viewer sessions, regardless of the project. The Interface view is saved in the interface of the project and is only available when that project interface is open and simulation results are available.