Significant Discrepancy in LoRa Device Current Consumption (SX1261 and generic node)

josh_hslu
Tue, 03 Jun 2025 07:53:47 +0000
Generic Node

Hi,

During power profiling, I discovered a surprising difference in current consumption between two LoRa devices: the generic node and a custom board (NUCLEO-L073RZ paired with the SX1261).

The custom board uses the NUCLEO-L073RZ, which features the STM32L0(Cortex-M0 processor). I have connected this to the SX1261MB2xAS Mbed shield containing the SX1261 LoRa chip. As far as I know, the SX1261 is known for its low power consumption, compared to the SX127x and SX1262.For this setup, I’m using the SWL2001,SWL2001.

The generic node, on the other hand, uses the STM32WL5CC, which includes both Cortex-M0 and M4 cores, along with an integrated SX126x LoRa module. I’m using the sensors_lorawan example from the corresponding GitHub repository.

Both devices are configured with:

Spreading Factor: SF12

TX Power: 14 dBm

However, the power consumption results are drastically different. Both images show the expected TX and RX1/RX2 windows

Custom board (NUCLEO-L073RZ + SX1262MB2xAS): Consumes on average 17 mA.

Generic node: has peaks at 25 mA, but overall averages around 4 mA.

Power consumption generic node:

Power consumption custom board (NUCLEO-L073RZ + SX1262MB2xAS):

Logs generic node:

Logs custom board:

Do you know why there is such a large discrepancy? Could it be due to differences in hardware initialisation or firmware configuration, or could there be an issue with the radio driver?

9 posts - 5 participants