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...

[goldwake]

Have you looked at the NRF52832? Its got all the BLE 5 features except for the range. Its got slightly better sensitivity than the NRF51 and the errata list isn't huge like the nRF52840. Also, its available now. The new SDKs don't support the NRF51 either.

[endnode]

Hi nordicdev,

1. Power consumption doesn't have really much o do with specification version, that's property of each chip and SW (stack) how well it gets implemented. There are ll the details of basic power consumption figures of nRF52840 chip in preliminary (objective) product specification hanging on Infocenter + all the power profiles of Nordic BLE stack are in Soft Device specification. So you can compute your theoretical numbers if you really need.
2. BT5 is almost nothing saying buzzword (or to be more precise it's name of 3-thousand pages document) so it will always depend on what features and parameters you use from BT4 or BT5:) No answer can be done from this, just general comparison of nRF51 and 52 families which was presented by Nordic on their blog several times (claiming nRF52832 being up to 80% more power efficient then nRF51 at the same use case;).
3. You've read some nice marketing materials, reality is indeed more complex;) Under some specific conditions it might be true but definitely not all the properties at once (already "long range" means coded PHY and hence much lower air-speed data rates then 1Mbit in BT 4.0-4.2, don't get confused by glossy marketing extracts for non-technical people;)
4. Sure, there are HW examples which can achieve easily 1kM of BT 4.x advertisement visibility on free air. Radio properties are still the same (it's 2.4GHz magic) and the only "helping" features of BT5 vs. BT4 are possibilities to use "coded PHY" (= lower effective bit rates which help error corrections and S/N ratio) and higher Tx Power (so you can certify your HW to be "loader" on transmitting side). All the rest is on your antenna design so if you do some monstrous yagi antenna (and will pass the regulatory certifications;) you can probably go beyond that 1kM even with standard BT4.x 1Mbit PHY.
5. This I won't comment, that's for Nordic (and they will tell you that preliminary release date is Q4/2017 and for all the rest you should contact your local sales rep).

Cheers Jan

[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

[nordicdev]

Hi Goldwake, thanks for the reply. Does it mean that there would be no SDK updates for nRF51 series? (in other words, is SDK 12.3.0 going to be the final SDK update for nRF51 series forever?)

[goldwake]

you'd have to ask Nordic about that but, SDK 13 doesn't support the NRF51 and ANT support for the NRF51 was only available until SDK10.