Hi,
If you are using the Adafruit MODULE then.
To quote Adafruit Description;
We even made the breakout 5V compliant, with a 3.3V regulator and level shifting, so you can use it with any Arduino or microcontroller.
That is you don't need to level shift, its all done on the board for you.
If you use the IC on its own, then you will have to provide the power supply and level shifting.
Tom... 