FAQ: Logic and Voltage Translation > Power and Thermals >> Current FAQ
Some datasheets do not specify what should be done with the thermal pad, such as in the image below:
The thermal pad is recommended to be soldered to the PCB and electrically connected to the ground for the best thermal and mechanical integrity.
It can be left floating, and does not have to be soldered down if thermals are not a concern for your design.
It is not recommended to be connected to any other pin.