Why when I measure the Idd current during operational mode do I get higher than
the 554uA as quoted in the maximum rating in the data sheet?
The conditions for Idd current measurements in the data sheet are for a Vin =
0V. This means that the output codes are all 0s. If the output codes are
toggling the current required to change the state of the SDO pin is increased
and therefore Idd current is increased. The worst case current will be when the
conversion result is 101010… The current drawn in a particular application will
also depend on the capacitive load on the SDO line.