RE: A default gain of nRF21540 FEM from the factory in a simple configuration

Lukáš — Thu, 07 Jan 2021 08:17:30 GMT

Hi,

The main reason for asking was that we didn't see the 20dBm or 10dBm on the output. However, it was for a different reason (we messed up timings in the Zephyr controller). Now it works as expected - when the mode is grounded, it is 20dBm, and otherwise, it's 10dBm. It is also true that that mode shouldn't be left floating.

RE: A default gain of nRF21540 FEM from the factory in a simple configuration

run_ar — Mon, 04 Jan 2021 12:30:47 GMT

Hi,

The mode pin is used to choose which of the pre programed gain settings should be used so I do not think you should leave this floating. See link to tx power setting below, you can choose between two settings:

POUTA_PROD (20 dBm +/- 0.5 dB)

POUTB_PROD (10 dBm +/- 1.5 dB)

https://infocenter.nordicsemi.com/pdf/nRF21540_PS_v1.0.pdf?cp=6_0_0_0#%5B%7B%22num%22%3A28%2C%22gen%22%3A0%7D%2C%7B%22name%22%3A%22XYZ%22%7D%2C85.039%2C593.298%2Cnull%5D