Hi Rene, I offer some replies to your comments:
> So the conclusion is that inserting a ferrite bead only does not create a > filter, before we never heard of L-Filters, only LC-filters. > THerefore there must be an decoupling capacitor across the VCC of the IC > and the ground plane. THe decoupling capacitor can either be a discrete > component or an VCC island under or very near to the IC. > The main points are 1) don't segregate the Vcc (i.e., use an island); and 2) passing Vcc through a ferrite bead creates emissions problems in high frequency circuits. > The VCC island is then connected to the main DC Island by above mentioned > ferrite bead coil. And this is what causes the problems.
