Calibre How to apply reduction or no reduction to selected nets
Summary
If you need specific nets to have reduced parasitic models and all other nets to have non-reduced parasitic models, or if you need to have all nets to have reduced parasitic models except a select few nets, then this Knowledge Base Article can help you achieve this result using the Calibre Interactive PEX GUI
Details
[1] Is it possible to apply the reduction settings to a specific net?
[2] Is it possible to not apply the Reduction settings to a specific net?
You can do both of these using the select net flow in concert with the incremental Parasitic DataBase (PDB) flow in the Calibre Interactive PEX GUI
For [1] Is it possible to apply the reduction settings to a specific net?
First, set the incremental flow to preserve the PDB through multiple PDB
generation steps under: Outputs -> SVDB -> Generate PDB incrementally
Second, set the run controls to run the first two steps of the 3-step flow under:
Run Control -> Advanced
Then exclude the net(s) of concern from extraction.
This will extract all not-excluded nets
(but it will not produce an output netlist because the formatter step will not be run)
To exclude the net(s) of interest:
Select the net(s) of interest for being excluded from extraction by:
Outputs -> Nets -> Extract parasitics for: Specified Nets
Top-Level Nets -> Exclude -> net_01 net_02 . . .
Make sure all reduction is not selected under:
Setup -> PEX Options
PEX Options -> Netlist -> Reduction and CC
Run PEX
All not excluded nets have been now extracted without reduction
They are in the parasitic database (PDB) awaiting netlisting in an upcoming step.
Second set the run controls to run the last two steps of the 3-step flow under:
Run Control -> Advanced
Then include the net(s) of concern in the extraction.
The next Run PEX extracts only the included nets.
and it will produce an output netlist because the formatter step will be run.
To include the net(s) of interest:
Select the net(s) of interest for being included in the extraction by:
Outputs -> Nets -> Extract parasitics for: Specified Nets
Top-Level Nets -> Include -> net_01 net_02 . . .
Make sure all the reduction you want to be done is selected under:
Setup -> PEX Options
PEX Options -> Netlist -> Reduction and CC
Run PEX
This will give:
All not-excluded nets extracted without reduction
All included nets (i.e. net_01 net_02) extracted with the chosen reduction settings
The netlist is produced from the incrementally loaded PDB.
For [2] Is it possible to not apply the Reduction settings to a specific net?
You need to run through the steps in [1]
But swap the (bold-red) reduction settings in the order of steps.
This will give:
All not-excluded nets extracted with the chosen reduction settings
All included nets (i.e. net_01 net_02) extracted without reduction
The netlist is produced from the incrementally loaded PDB.