SX1509 16 Output I/O Expander Breakout

I just got this I would like to know exactly what "I/O banks can operate between 1.2V and 3.6V (5.5V tolerant)" means does this mean I still put 3.3 volts on the 3.3 volt pin?

Did you think to look in the data sheet ...?

The device has 3 power pins - "VDDM" is the main power supply for powering the chip. This is 3.3V. Then there is "VCC1" and "VCC2" - these are the power supply pins for the two halves (0-7 / 8-15 respectively) of the IO pins. Connecting 2V to VCC1 will cause IO pins 0 thru 7 to use 2V for their HIGH value. Applying 3V to VCC2 will cause IO pins 8 thru 15 to use 3V for their HIGH value. The input thresholds are relative to that same VCCx voltage