Maximum Stub Exposed Length
Set a maximum length for exposed stubs to prevent unintentional antenna effects. This is particularly important for high-fre-
quency signals where wavelengths are shorter. A general rule of thumb is to keep stub lengths below 1/20th of the signal's
wavelength.
Steps:
1. Similar to the stub length rule application, open the Constraint Manager.
2. Create an electrical CSet in the Electrical Constraint Set > Routing > Wiring worksheet.
3. Once created, scroll horizontally and fill in a max exposed trace length (ideally below 1/20th of signal wavelength) in the
Max Exposed Length field in the row of your desired ECSet.
4. Finally, go to the Electrical Constraint Set > Net > Routing > Wiring worksheet.
5. Click and apply the appropriate ECSet onto the desired net by selecting the ECSet from the Referenced Electrical CSet
column. The rule is automatically applied to that net.
57 www.cadence.com
OrCAD X High-Speed Digital Design Guide
