nRF52811 LNA+WiFi maximum power to input

RE: nRF52811 LNA+WiFi maximum power to input

JONATHAN LL — Tue, 01 Mar 2022 11:08:02 GMT

[quote user="ojousima"] Core issue however is that we have no way of knowing when the WiFi is active to control the LNA or any other external switch. [/quote]

Then this is indeed a difficult issue and a switch would not help in that case.

I would stick to the old SDK where there radios still can work as intended. You can run som tests on a handfull of the devices to see if there is any issues wit LNA always on, it is a bit on the risky side in my opinion, so it is not something i can recommend, and in the long run i would expect to se more issues on devices configured wit the LNA always on.

Keeping the LNA off could be the better option of 2 and 3 if the range is not that badly impacted

[quote user="ojousima"] so if nRF52 has any kind of "RF overload" warning signal we could force the LNA off to protect the nRF52[/quote]

No, dont have a feature like this.

Regards,
Jonathan

RE: nRF52811 LNA+WiFi maximum power to input

Otso Jousimaa — Thu, 24 Feb 2022 09:07:05 GMT

[quote userid="91187" url="~/f/nordic-q-a/85068/nrf52811-lna-wifi-maximum-power-to-input/354734#354734"]So i would ask the ESP32 SDK developers to address the issue as fast as possible. [/quote]

Let's hope this gets priority.

[quote userid="91187" url="~/f/nordic-q-a/85068/nrf52811-lna-wifi-maximum-power-to-input/354734#354734"]To be sure that you keep the performance you al ready have i would sick to an older ESP SDK, if not then what is the option to do some HW changes on the device. Including a RF switch that that can be used to disconnect the NRF and or the LNA would solve the current issue. [/quote]

HW changes are not feasible for the devices already in the field, so we need a SW solution.

How would RF Switch help us in this case? We have GPIO control to LNA both from nRF52 and ESP32, so if nRF52 has any kind of "RF overload" warning signal we could force the LNA off to protect the nRF52. Core issue however is that we have no way of knowing when the WiFi is active to control the LNA or any other external switch.

[quote userid="91187" url="~/f/nordic-q-a/85068/nrf52811-lna-wifi-maximum-power-to-input/354734#354734"]Do you have any timeline on when the bug will be addressed by ESP SDK developers? [/quote]

No, we try to get a firm answer on this.

Thanks,

Otso

RE: nRF52811 LNA+WiFi maximum power to input

JONATHAN LL — Thu, 24 Feb 2022 08:40:41 GMT

Hello,

So i would ask the ESP32 SDK developers to address the issue as fast as possible.

[quote user=""] Is it possible that RF energy at +10 dBm in WiFi antenna gets coupled at -2 dBm to Bluetooth antenna? The antennas are a few cm away from each other and I have no intuitive understanding if the worry is reasonable or nor.[/quote]

Yes, this is a possibility that it might happen. Cant say without measuring on the device.

So if more than 10dBm gest coupled to the radio or the LNA it can take damage. And living the LNA on all the time could also damage the nRF.

To be sure that you keep the performance you al ready have i would sick to an older ESP SDK, if not then what is the option to do some HW changes on the device. Including a RF switch that that can be used to disconnect the NRF and or the LNA would solve the current issue.

Do you have any timeline on when the bug will be addressed by ESP SDK developers?

Regards,
Jonathan