Z-target Lumped vs Distributed

Discussion created by m3lg4ng on Jul 10, 2019

Is the calculated Z-target for a lumped AC decoupling analysis different than for a distributed AC decoupling analysis?


The distributed AC decoupling analysis uses currents per pin (assume 1A, 1 out of 10 pins) as the lumped AC decoupling analysis uses current per device (assume 10A). I assume that the Z-target from VRM (voltage regulator module) to the area of the device is the same as for the lumped (10A), but as soon as it starts to spread out (KCL, kirchoff current law) the Z-target may change (increase). Is this a viable argument that the Z-target for a distributed AC decoupling analysis (Z-target x number of pins) is different than the lumped analysis? 


Would like to hear some thoughts.


Personally I cannot find any reference that the Z-target deviates, so I'm with the conclusion that the same Z-target is legitimate for both analyses.