Via Stubs and Propagation Delay Script

Via Stubs and Delay - GUI

The Script can find Via Stubs and Set Via Propagation Delay.

Enter the Max Stub length allowed in mils. 

Select Top, Bottom or both to Find and Select Stubs.

Enter the desired max Via Stub length.

Double Clicking Max Stub will set Max Stub = to 1/2 Board's Copper Height.

For zero length stubs enter 0 in Max Stub.

Then select Run.

The script unshelves and repours polygons then starts checking the vias.

Store and Recall Buttons may be used to save and recall selected Via Stubs.

End or Via Stubs.

Via Propagation Delay Notes:

Select more or less than 1 Via to set the Propagation Delay of all Via Drill Pairs.
Select only one Via to set the Propagation Delay of all Via's in the same Drill Pair.

Click the Delay Button to update the Propagation Delay.

Note Altium calculates the delay as the proportion of the via the signal path between the start and stop layers, this is not the physical ength of the via. It is the signal path electrical length.

Example: A board with a total thickness of 61.8mil, including a total of 1mil of solder mask and 2mil outer Cu thickness, where the electrical via length is calculated as Total - Soldermask - 1/2 top Cu - 1/2 bot Cu = 58.8mil.  

Altium uses 1/2 of the copper height of the starting and stopping layers.

Example:

The Calculated Delay of the Via is 10.917pSec for a signal path length of 58.8mils.

Related Links:

Signal Integrity Characterization of Via Stubs on High-Speed DDR4 Channels | 2020-05-14 | Signal Integrity Journal

https://resources.altium.com/p/your-complete-guide-stub-analysis

For more inforamation about this script Contact Parts (Randy Clemmons)

That's it !