[SOLVED] EM VIA volations:Average current density to calculate no.of vias.Why not RMS current?

[muthu21888]

Hi all,

During EM checks we determine how many vias are required based on average current density divided the current limit per via.

Why are we using average current density to find the number if vias to pass EM?

Why dont we use RMS current to calculate the number of vias required?

Dont we expect joule heating in vias?

Please clarify my doubts.

If you have any documents to understand please mention that.

Thanks in advance.

Regards,
Esakki

 

[WoAiHua]

May I know the formula for average current density and RMS current density? it is for own use. thanks.