Bluetooth 5 power consumption.

[nordicdev]

Hi,

1. I know this is a Bluetooth 5 spec question, but wanted to know the practical figures for current consumption when nrf52840 is used as both central and peripheral.

2. Also, will this current consumption be more in Bluetooth 4(nRF51822) than Bluetooth 5(nRF52840)?

3. I have read that Bluetooth 5 has increased range, yet lesser power consumption than Bluetooth 4. How is this possible to have a less power consumption yet increased data rate and increased range?

4. Also, even with Bluetooth 4 (nRF51822), we were able to get a range (in open air) of more than 100m (as opposed to 50m)? We did use a good antenna, so why cant we just use good antenna and use bluetooth 4 instead of bluetooth 5 if the intention is to just increase the range?

5. We have worked with nRF51822 for a while and find it to be awesome. However, we found nRF52840 has a comparitively long list of anomalies (in errata sheets). Do you have any timeline when the nRF52840 would be stabilized like nRF51822 with less number of anomolies?

I am having a tough time advocating for nRF52840 with the other team members, so please help...

[Jørgen Holmefjord]

Hi,

1. The main current consumption of the device will be the radio current. You can see radio current consumption in nRF52840 for transmitter and receiver.
2. The current consumption will depend more on the device used than the Bluetooth version. In general, the radio current of nRF51822 is slightly higher than the nRF52 series in most configurations.
3. You can't have increased throughput and increased range at the same time. Long range mode will code each bit into 8 bits, giving you better sensitivity, allowing for up to 4 times the range of BLE 4 specifications. Long range mode gives you a throughput of 125 kbps, but the on-air datarate will be 1 Msps. The current consumption will thus be similar to the radio current of 1 Msps. High throughput mode increase the on-air data rate from 1 Msps to 2 Msps. This allows you to transmitt 2 times the date of BLE 4 in the same amount of time. If you need to send the same amount of data, the time the radio needs to be on is decreased, lowering the average current consumption.
4. If you don't need longer range than what you achieve with BLE 4, you don't need to switch to BLE 5 long range. Note that the achievable range in BLE 5 will still be ~4 times what you get with your BLE 4 setup.
5. nRF52840 is currently only available in engineering samples. A production variant will be released within the end of the year. At this point, the errata list will be reduced.

Lastly, I would strongly advice you to select one of the nRF52 series devices (nRF52840, nRF52832 or nRF52810) for your design. These device provide much more features, lower power, and more flexibility to you product.

Best regards,

Jørgen