Skip to main content
Associate
August 25, 2025
Solved

VDD_TCXO not used at STM2WLE5JCI6

  • August 25, 2025
  • 1 reply
  • 673 views

Hi,

We are using the STM32WLE5JCI6.

In our design, the TCXO (HSE) is powered directly by the 3.3 V on-board power supply, and the VDD_TCXO pin is left unconnected.

 

Is this acceptable?

Should we avoid using the Set_TcxoMode command in this case?

Thanks for any help

Best answer by STTwo-32

Hello @Adielfr 

Yes, you can use an external power supply and not the VDD_TCXO pin. This approach is valid as long as the external power supply meets the TCXO's voltage and current requirements. The VDD_TCXO pin is specifically designed to provide power to the TCXO, but it is not mandatory to use it if an external power source is available and suitable. 

For the Set_TcxoMode command, you should not use it in such configuration.

Best Regards.

STTwo-32

1 reply

STTwo-32
STTwo-32Best answer
Technical Moderator
September 23, 2025

Hello @Adielfr 

Yes, you can use an external power supply and not the VDD_TCXO pin. This approach is valid as long as the external power supply meets the TCXO's voltage and current requirements. The VDD_TCXO pin is specifically designed to provide power to the TCXO, but it is not mandatory to use it if an external power source is available and suitable. 

For the Set_TcxoMode command, you should not use it in such configuration.

Best Regards.

STTwo-32