Query related to Decoupling Analysis and Ferite Bead

Discussion created by jagdish.goswami on Feb 2, 2014
Latest reply on Feb 10, 2014 by cristian.filip

I have some basic Query While doing Decoupling Analysis of one of the board. Please help me out in resolving this query.

The scenario of my board is given below



n1=Power plane (1.375V)
n2=Power Plane (1.375V)

output Voltage of VRM = 1.375V
Ripple = 2.5%

IC1 is drawing ~ 3A of current from plane n2


I am doing the Decoupling Analysis of plane n1.
so I am assuming FB as one of the sink which is taking 3A of current from n1,
target impedance will come out to be only 19.462 mOhm below FB

My Query is am i doing it correctly by taking FB as one of the sink with 3A of current?

Do I need to make sure that the impedence graph is below target impedance even at the input of FB?