TX active mode selection on BB-STM32WL

[UweBonnes]

Hello,

on BB-STM32WL, R4 and R5 allow TX active mode selection between 14 and 20 dbm. Default selection is 14 dbm. Is this selection user changeable?

[LubOlimex]

Yes. As you noticed by default 14 DBM is set with R4 not placed and R5 is 0R. To change to 20DBM unsolder the 0R resistor and place it on the R4 position (leaving R5 unconnected). This is visible in "Table 1" the schematic.

[seb30]

Yes. As you noticed by default 14 DBM is set with R4 not placed and R5 is 0R. To change to 20DBM unsolder the 0R resistor and place it on the R4 position (leaving R5 unconnected). This is visible in "Table 1" the schematic.

Hi,
I had a look at STM32WLE5 datasheet and according to "high output power PA" schematic, in order to have 20dBm output, you also need to wire VDDPA to supply > 2.7V.
In your schematic (rev C), VDDPA is hard wired to SMPS output (1.55V) so my question : how can you achieve 20dBm in that configuration ?
Best Regards.

[LubOlimex]

I think you are correct. Changing the resistor seems insufficient for high power mode.

I believe that you need to disconnect VDDPA from 1.55 wire and wire VDDPA to 3.3V input (VDD being 3.3V). This might not be easy to do as it is.

I will propose the designers to have a look at it for future hardware revisions. Not sure if we have space for two resistors or jumpers. Not sure how important is the high-power mode for our design. Yet, I will make sure they get the message.