nRF 52832

[RADHIKA RAINA]

nRF 52832 supports LE 1M and LE 2M PHYs. Which PHY leads to less power consumption in transmitting mode and why?

[Susheel Nuguru]

Hi Radhika,

This is unfortunately a tricky one to answer when it comes to radio modulation and overall powerconsumption. Using the 2M PHY can actually lead to less power consumption in the transmitting mode. This is because the 2M PHY effectively doubles the data rate to 2 megabits per second, or 2 Mbps, which means that compared to 1Mbps, you only keep the radio on half of the time. I do not think that there is a significant difference in clock module power draw between 1Mbps and 2Mbps but as mentioned above RADIO on time is less in 2Mbps. Since the data is transmitted at a higher data rate (faster), the radio needs to stay on for less time, which decreases battery usage.

However, it's important to note that the downside of using the 2M PHY is the decrease in receiver sensitivity, which translates to less communication range. Which makes 2Mbps perfect for very close range peers. If you want to maximize the range of your transfer, you would need to use the CODED PHY, but this comes at a considerable cost to the throughput of your link.

In general, you are less susceptible to noise and on-air data corruption the shorter you are transmitting. Switching to 2M PHY will require half the time to transfer the same payload as if you were using the 1M PHY, and so you will actually have less data corruption on the link when you use the 2M PHY.