We used the RAK3172-SiP in our project.
We turned the unit on and off about 50 times - the consumption of the unit is about 9 mA. Everything works as normal for us.
Then we connected to the RAK3172-SiP via the SWD interface (we tried the STLINK v2 mini adapter and the STM32 ST-LINK Utility) and looked at the data in the internal memory (there is the factory firmware).
Then we disconnected the SWD interface and reset the power supply of the 3.3V block.
After re-powering our block began to consume abnormal current. During the analysis it was found that the resistance relative to GND of the VDDRF and VDDPA circuits is not more than 4 ohms.
We disconnected power from the VDDRF and VDDPA circuits. After applying power, the consumption of the module was 9 mA and about 3 mA when the RAK3172-SiP was put into reset.
We installed a new RAK3172-SiP into our board and repeated the experiment - the result was similar - a breakdown to GND on the VDDRF and VDDPA circuits.
Can you give us an idea what could be wrong? Thanks in advance.