RE: 5V vs 3.3V

JeanLeMotan — Wed, 13 Sep 2023 20:56:49 GMT

Yes, we cannot use 5V for the nrf in our design. So sticking to 3.3V and moving the switching regulator away from the sensitive sensors. Thanks a lot for the help!

RE: 5V vs 3.3V

Kazi Afroza Sultana — Wed, 13 Sep 2023 08:00:20 GMT

You are welcome. 🙂 Is the problem solved now?

RE: 5V vs 3.3V

JeanLeMotan — Thu, 07 Sep 2023 20:32:06 GMT

Thanks a lot for the detailed answer. I totally missed the 3.9V max for VDD_GPIO. We'll stick to 3.3V and try to reduce the noise through other means.

RE: 5V vs 3.3V

Kazi Afroza Sultana — Thu, 07 Sep 2023 10:21:22 GMT

Hello,

The nRF9160 has a single main power supply VDD. The internal components are powered by integrated voltage regulators. Th GPIO input/output supply is independent of VDD through VDD_GPIO. This enables easy match to signal voltage levels in the PCB.

You can see from the table 3GPP compliancy is 3.3V (Including voltage drop, ripple and spikes.RF 3GPP compliancy requires 3.3 V)

The supply voltage VDD of nRf9160 is ranged as -0.3 to 5.5V and VDD_GPIO is -0.3 to 3.9 V. But these 5.5V and 3.9V are the absolute maximum ratings. Maximum ratings are the extreme limits to which the chip can be exposed for a limited amount of time without permanently damaging it. Exposure to absolute maximum ratings for prolonged periods of time may affect the reliability of the device.

It is not recommended to use high voltage with high frequency, high capacitance loads unless needed, as this may increase noise level and affect radio receiver performance. High drive/high load should especially be avoided on GPIO pins close to the radio front end.

I think if the source is 5V, you should use a DC-DC converter to keep the voltage down in an efficient operative range.

Thanks.

Kazi