STM32 external OPAMPx_VINM pins

SYako · ‎2021-12-17

Hi, I'm working on a project which involves STM32L476QEI. It has external dedicated OPAMP1_VINM and OPAMP2_VINM (M3 and M4 pins). If I'm not going to use the opamp functionality, do I have to connect them to the ground or leave them floating? What I learn from CubeMX is that I can use them to remap connections to free up GPIO. Are there other possibilities that I missed?

Peter BENSCH · ‎2021-12-19

When not in use, I would recommend to connect them on GND, even if these are not digital inputs with Schmitt trigger. In the case of the BGA132, these are dedicated pins in order to minimize the bias current (see RM0351, section 23.3.3):

The dedicated pin is only available on BGA132 and BGA169 [...] package. This configuration provides the lowest input bias current (see datasheet).

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

View solution in original post

Peter BENSCH · ‎2021-12-19

When not in use, I would recommend to connect them on GND, even if these are not digital inputs with Schmitt trigger. In the case of the BGA132, these are dedicated pins in order to minimize the bias current (see RM0351, section 23.3.3):

The dedicated pin is only available on BGA132 and BGA169 [...] package. This configuration provides the lowest input bias current (see datasheet).

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.