UCD9081: external reference of 2.5V

The internal 2.5 reference of the UCD9081 is quite loose.  The data sheet talk a little about using a external 3.3 reference for more accuracy.

Is there any reason a external 2.5V Reference won't work?

Any special precautions to take?

Thanks,

Dan

2.5V internal is 2.35V to 2.65V