You need to look at what the lowest value of Vraw can be.
The regulators on the ProMini are low dropout linear type, but you will not get a regulated 5V output if you only put 5V in.
There has to be some headroom, so you need to seroiusly consider what your power supply is going to be?
A Pro-mini will normally have ONE voltage regulator, designed to go from Vraw to whichever voltage the board is set for. Vreg appears on the Vcc pin(s), and you can also feed in an already-regulated voltage at Vcc instead of an unregulated voltage at Vraw.
The regulator is tiny and lacks much in the way of heat-sinking, so you can't get a lot of power out of it, especially at input voltages that are substantially above the output voltage.
What the Pro-mini LACKS is a SECOND regulator. Uno-like boards will have one regulator to provide 5V from the DC power jack, and a regulator that provides a 3.3V power source as well.
Thanks for the info, the sensor I am using only draws 1.1mA so hopefully a generic 3.3 board will suffice! I will try it and if it does not work, I will look at feeding a regulating voltage onto the Vcc pin.