Using Ferrite Bead for VDDA pin

[Asraful]

I am trying to design a dev board using stm32 mcu but the issue is I cannot select a ferrite bead I know some basics of ferrite bead but what should I consider from my mcu’s side to select a ferrite bead for it can anyone help me about this or is there any application notes for this

[Uwe Bonnes]

The bead should isolate VDDA from high frequency disturbance from outside. So it should have a high Z at low frequency, with sensibile voltage drop caused by the DC resistance and acceptable drop in Z caused by the current through the bead saturating the ferrite. Fot higher frequencies, Z gets more resistive, so it gets harder to for a LC tank by the bead and capacitance bt decoupling C, the traces etc. and ferit beads are used and not normal inductivities.

[gregstm]

I used Murata 603 (inch) size ferrite beads on my board (I assume and trust that you are talking about surface mount ferrite beads and not the ones you pass a wire through). There seemed to be more application notes around years ago when I was first designing stuff, but I did find the following that could be interesting.

https://www.analog.com/media/en/technical-documentation/application-notes/AN-1368.pdf

And here is info at the Murata site:

https://www.murata.com/en-eu/products/emc/emifil/overview/lineup/bl

[Asraful]

Thanks for the info but my issue is what should I consider suppose I going to design a board with stm32f446re