nRF9160 - Why LEDs have wideband noise?

RE: nRF9160 - Why LEDs have wideband noise?

helsing — Wed, 27 Jan 2021 10:44:30 GMT

Looking into how different types of diodes generate noise is an interesting read, touching on some interesting topics. However, a solid red LED should normally not be of any concern. As always, please ask us for a free HW review on the NordicSemi related part of your design when you are ready.

RE: nRF9160 - Why LEDs have wideband noise?

pctj101 — Fri, 22 Jan 2021 19:44:12 GMT

Ah okay. Yeah if PWM then sure the edges and harmonics are understandable sources of concern. Just wanted to make sure a “solid red” LED wasn’t an issue :)

RE: nRF9160 - Why LEDs have wideband noise?

helsing — Fri, 22 Jan 2021 16:23:10 GMT

In general, HW design EMI must be always considered. I checked with a few team members that regularly deal with or review HW issues, and they did not report noise from LEDs as a common problem in customer designs. My impression after these discussions is that PWM control issues(and PCB traces) with their harmonics is of more of importance.

When It comes to the noise related to the operation of the LEDs themselves, I have not bee able to conclude on anything yet.

RE: nRF9160 - Why LEDs have wideband noise?

helsing — Mon, 04 Jan 2021 14:24:53 GMT

Hi Jeff,

Thank you for these interesting questions. I will start working on them tonight.

Best regards,

Håkon