VIAS

[Norbert]

I am length-matching a DDDR3 T-branch topology but I realized I need to add the via's length. Is there a proper way to find the length of vias. I have been caluculating them using the stuckup but I am sure there should be a proper way of find the length of a vias

[mairomaster]

For T-branch it's very useful to setup xSignals in Altiuml. Then you will have a direct measurement of the signal length to each chip. Check some older topics (use the search) - xSignals have been discussed before.

[robertferanec]

Norbert, do you mean add the VIA length into ADDR/CTRL/CMD? Usually there is tollerance at least 50mil on the signals, so many times if you make the signals similar length, you should be in the tollerance. However, if you would like to make it perfectly right, as mairomaster suggested, you can use xSignals: ​Altium – How to use xSignals ( in Fly-By, T-Branch + Other useful things )

[Norbert]

Thank you for your help. I used the techniques you tought in ur courses then I finished with the xsignals at the end. The different between the DDR3 classes for memories devices at the top and at the bottom is vias length. But if there is a tolerance of 50 mils, it should be ok.