nrf52832 RF power accuracy

[JPierpont]

The OPS states the maximum transmitter RF power accuracy to be +/- 4 dB. Does this imply that if the power is set to +4dBm it could vary from 0 dBm to as much as +8 dBm? What is the typical variation in power that should be expected? Is this accuracy applicable from chip-to-chip or from BLE channel-to-channel or both? Under what specific conditions should it be expected that this variation of power level will be observed (temperatures, supply voltage variation, etc.)? This is a large variation and we need to better understand its impact to our predicted part-to-part communication range.

[ovrebekk]

Hi

In theory the output power in the +4dBm setting could be anywhere from 0dBm to +8dBm, yes.
That being said the distribution of output power is highly Gaussian (normalized), with the majority of chips being much closer to the set value.

Under normal conditions I doubt you will see much more than +/- 2dBm deviation at worst.

Voltage does not impact output power, as the radio uses a much lower voltage that is regulated internally.

Temperature can impact output power, and in general a higher temperature leads to lower output power.

The RF channel can impact the output power also, but this depends on the external filters and antenna matching circuitry and not the chip itself. An ideally tuned RF design will have the highest output power in the middle of the band, tapering off slightly towards the lower and higher end.

Best regards
Torbjørn Øvrebekk

[JPierpont]

Hi thanks for your reply. Is the +/- 2 dBm deviation defined from lot-to-lot or from channel-to-channel on the same chip? How is the output power effected by changes in supply voltage (minimum to maximum)?

[ovrebekk]

Hi

Assuming little variation in temperature I would expect +/- 2 dBm variation even between lots. Channel to channel variation should be lower.

Supply voltage does not affect output power.

Best regards

[AkiraZhao]

Hi，

    I got your point that the tx output power would be much closer to the set value. 

But there will be the other question appeared. As below the datasheet pic.

+/- 4dBm is the Max value, the typical value is filled with blank.

My question is how would the worst conditions happen under normal room temperature.

Best regards

Akira

[Kenneth]

AkiraZhao said:

My question is how would the worst conditions happen under normal room temperature.

We don't have numbers for that, we only provide tolerance over entire operating conditions in this case (over temperature and supply voltage).

Kenneth