I'm developing an STM32-based device, one of whose functions is to periodically monitor the main power 12V battery voltage.
I created a simple switching circuit with a voltage divider. I have added a pull-down resistor (R7) to the MOSFET gate, to make sure the switch is always off. On the PCB, I placed these components on the 'dirty' ground corner, near the 12V source (and the switching DC-DC converter). It has a ground plane which connects with the MCU's ground plane at single point.
So the question is: Will switching the VBAT_SENSE_EN pin to low by the MCU, cause a ground loop to the 'dirty' ground? Will this effect be significant? Or should I eliminate R7 and use the internal MCU pull-down?