Noise requirements on power supply to nRF54Lxx?

RE: Noise requirements on power supply to nRF54Lxx?

Asbjørn — Wed, 05 Feb 2025 14:18:38 GMT

Yes, normally that would be my assumption. I assume the DCDC from 24V would be familiar with noise sources related to 24V systems, but also worth verifying the output from the DCDC as I said and if there are noise components still visible on the output of the 24V DCDC to add additional decoupling of those noise components before it's fed into the nRF54L15.

Best regards

Asbjørn

RE: Noise requirements on power supply to nRF54Lxx?

Jose Ojeda — Wed, 05 Feb 2025 11:35:51 GMT

OK, so a normal switch mode DC/DC power supply from 24V to 3.3V should be enough without any extra filtering of the 3.3V when I have the decoupling capacitors as suggested in your reference design close to the nRF54L15 chip?

RE: Noise requirements on power supply to nRF54Lxx?

Asbjørn — Tue, 04 Feb 2025 10:26:16 GMT

Hello Jose,

We have added decoupling on the power supplies in our reference design to suppress normal/common noise frequencies. You should be able to use standard normal DCDC supply to deliver voltage in to the nRF54L15. That said, if you have a system you know produce some specific noise at a potentially difficult frequency, we would recommend adding additional decoupling capacitor on the supply in to the nRF54L15. Normally though this isn't a problem, but every customer have a slightly different noise source and some have more complicated setup than others.

Normal DCDC should be fine. If you see noise levels on the output from the DCDC that you think is stemming from the 24V source or system, then decouple it on the DCDC output. The levels that becomes difficult depends on the noise frequency as well. So yes, if you have noise that you can detect on the DCDC output, we would recommend to decouple it and smoothen out the voltage going into the nRF54L15.

Best regards

Asbjørn