Is the output RF power depending on the input voltage of the module or any other functionality?

Onethinx Core LoRaWAN module uses the internal DC-DC regulator of the SX1261 radio chip. We are using the DC-DC regulator, because in the SX1261, the power efficiency of the transmitter is maximized when the internal DC-DC regulator is used.

When using DC-DC regulator, the supply voltage will directly affect the current consumption of the SX1261 radio chip.

:point_right:Therefore, the output RF power does not depend on the input voltage (or any other factor).

The parameter that does depend on input voltage is input current of the SX1261 radio chip

The following graph shows that the output power is the same as programmed power across all voltages (min 1.8V to max 3.7V).


Figure 4-5 shows the current consumption of the SX1261 LoRa radio chip depending on the programmed power and input voltage. Programmed power is the same value as the output power as can be seen in Figure 4-7.

At +10 dBm:

  • Input Voltage = 3.7V, Current = 17 mA
  • Input Voltage = 3.3V, Current = 19 mA
  • Input Voltage = 1.8V, Current = 34 mA

It is important to note that this higher current consumption is only occurring during sending, which is a small portion of total time (few hundred milliseconds), as the device will mostly be in sleep mode. However, it is important to know this current consumption so proper battery (which can handle this peeks) can be chosen.

Regarding Bluetooth current consumption (PSoC 63 datasheet page 67):

All in depth details regarding current consumption of different parts of the PSoC 63 chip found on our module can be found in the PSoC 63 datasheet, in the chapter Electrical characteristics (from page 38 to 68).

Semtech SX126x datasheet:
PSoC 63 datasheet: