Depending upon the VDDIO voltage, and voltage range appplication selects, following options are available:

For low voltage or high voltage setting, two IBIS files for following voltage range:
hr = high range >>> 3.0 V to 3.6 V 
lr = low range >>>> 1.71 V to 1.98 V

For wide range setting, three IBIS files are available for following voltage ranges:
nr = normal range >>> 2.7 V to 3.6 V
dr = derated range >>>  1.98 V to 2.7 V 
dr2 = derated2 range >>> 1.71 V to 1.98 V

Each port has separate rails so they can be powered by different voltage levels. 

If the application requires the pad voltage to span wide voltage range,  the RT600 supports a setting called wide range mode which is default setting
In this mode, pad current consumption is higher (10s of uAs) since detector is enabled to sense the VDDIO voltage.

To save power, the detector can be turned off by using low voltage range or high voltage range. This is what typically the application will use.

Using the POWER_SetPadVolRange power API call, the pad voltage range can be set accordingly.
