Can we use Ferrite Bead with STM8S MCU?

[despicableme]

Hi,

Can we use a ferrite bead with STM8S MCU for VCC pin along with the recommended decoupling capacitors at the VCC pin.

 

Thanks in advance.

[Peter BENSCH]

Well, it depends on which side of the capacitor you want to connect the ferrite bead.

The ferrite bead should not be placed between the MCU VCC pin and the decoupling capacitor. The capacitor should be connected directly to the VCC pin, and the (optional) ferrite bead is normally placed in the supply line before that local decoupling node.

Hope that answers your question?

Regards
/Peter

[despicableme]

Thanks Peter. That answers my query.

is there any recommended value to use.?

[Peter BENSCH]

The need for a filter such as a ferrite bead always depends on the specific environmental conditions and your requirements. Typically, no filter is needed on VDD, but on VDDA it can very well make sense to use either a ferrite bead, an inductor, or even a π filter. You can find further details on this in AN2834, for example, or here in the community if you search for filter or ferrite.

Regards
/Peter