STM32WLx5 min LoRa operating voltage

[surumadurum]

Hello,

there are different statements on the minimum operating voltage for LoRa operation.

STM32WL5-PWR paper says 1.95V,
STM32WLE5 ref manual says 1.8V (section 5.3.3 Transmitter).

What's correct?

[Filippo_Malleo · Accepted solution]

Hi surumadurum,

the STM32WL5 can work down to 1.8V, but if you enable the Radio end of life (EOL) monitor, via RFEOLEN bit in the PWR_CR5 register, the software stops radio activities if the VDD crosses the End-of-life low-threshold voltage (VEOLL). The latter value you can find in the datasheet, as well as the VEOLH threshold voltage.
As you can see from the datasheet, for 868 MHz the VEOLL value is 1.96 V.

For more information, you can refer to the "Radio end of life (EOL)" paragraph in the reference manual.

BR,
Filippo

[surumadurum]

Ok, thanks a lot for the clarification!

So, does that mean the bottom-line is LoRa operation is specified down to 1.8V, but only recommended above 1.96V in 868Mhz region?

[Filippo_Malleo]

Hi surumadurm,

the device can operate down to 1.8V, but using the radio end of life monitoring feature, it is recommended to work down to the VEOLL voltage.

BR,
Filippo