CPA RLCG Modeling Using Partitioning

Whole package signal net extraction comprising hundreds of signals could be time-consuming when the CPA-Q3D solver is selected. One option is to use the default FEM solver, and move the slidebar to Optimal-SI Extraction under the CPA tab of the SIwave Options window. If you prefer the Q3D solver, CPA provides a partitioning approach to efficiently extract a larger number of signal nets.

With the Q3D partition enabled, CPA divides all of the signal nets into several partitions, each of which consists of a number of nets that are all close to one another. This is done in order to efficiently and accurately analyze the entire package.

To enable partitioning for Q3D solver:

  1. Under the CPA tab, locate the Q3D Partitioning panel. Click Enable.
  2. If appropriate, set the parameters for the Q3D partitioning (auto plane extents cutting distance, preferred net group size, XY coupling distance, Z coupling distance).
  3. To see a preview of the partitioning, click the Preview button. The Preview Partitions window appears. Use the Partition pull down to select a partition; that partition is highlighted in the Modeling workspace. The preview does not require partitioning to be enabled.

Guidelines to enable partitioning:

  1. The Partitioning option needs to be enabled in the Q3D Partitioning CPA options.
  2. Passive RLC components are not supported and the extraction is confined to physical routing.

All selected nets (both PG and Signal types) are partitioned and extracted by default. If only the SI extraction is of interest, then select the Ground P/G nets for SI Extraction check box. This facilitates a more efficient extraction where only the signals are partitioned and the selected PG nets act as return path.