Measuring AC Voltages Directly with the AD7768-4

Hi,

I am looking to directly measure a [-2.5,2.5] VAC Signal with the AD7768-4 Analog to Digital Converter. My original plan was to have Vdd=2.5V, Vss=-2.5V, but I'm wondering how to wire the +/- Reference Voltage Inputs. Can I simply use the ADR4525WBRZ-R7 with REF(+) as 2.5V and REF(-) tied to GND, or does REF(-) need to be -2.5V?

I know that any Analog Input cannot exceed the Vdd->Vss limit, but not sure if the same rules apply to the REF +/- terminals. I'd rather measure the AC signal raw without upshifting to a range of [0,5] V, although this would be easier to set up on the ADC.

Thanks for your help!