nRF9160 Ferrite Beads on VDD1 & VDD2

[Rulu]

According to the recommendations a Ferrite Bead (FB1) shall be connected to VDD1 (together with de-coupling capacitors).
Should VDD2 also have a Ferrite Bead connected?

Noise to/from the nRF9160 via VDD2 is not filtered the same way as via VDD1..
Have either two Ferrite Beads or none?

Has Nordic done testing on this?

[JONATHAN LL]

Hi,


VDD2 does not need a ferrite bead, following the recommendations form the Hardware integration guide is sufficient. 


Reason for the extra filtering on VDD1 is due to how it is connected in the SiP:
VDD1 is connected to the DC converter input of the nRF9160-internal PMU that supplies the System on Chip (SoC). VDD2 is connected to the DC converter input of the nRF9160-internal PMU that supplies the RF Power Amplifier (PA).


Hope this clears up any confusion.

Regards,
Jonathan