AD5700-1 Supply Voltage

I am not achieving the 1.71V minimum supply voltage specified for the AD5700-1.

The lowest I can achieve is 1.83V while the device is still outputting a modulated signal. Any lower (1.827V) and the signal disappears completely. This is measured at the Vcc/IOVcc pin of the device with a maximum ripple of 6mVp-p.

I have the device configured to use the internal oscillator and reference, and there is a series 470ohm resistor suppling Vcc/IOVcc.

For reference, I noticed that the silicon was changed for date codes 1303 and later to allow for this lower 1.71V supply voltage (down from 2V previously) but this particular IC under test is dated 1310.

There is concern that the voltage drop across the 470ohm series resistor brings the supply voltage dangerously close to the 1.83V figure tested above, when the device operates at the worst case current listed in the datasheet (285uA+270uA).

I am not aware of any damage this IC could have sustained to bring it out of spec but it is the only IC I currently have available.

Any suggestions would be appreciated?