What does the "TUE" or "total unadjusted error specification mean?
"TUE" or "total unadjusted error" is a measure of a channels worst case output error without any user calibration.
So for example, the AD5421 has a TUE error specification with external Rset of ±0.048%FSR. This TUE error takes into account the offset, gain and INL errors, including temperature drift, as well as the long term stability. As these different errors are affected differently by temperature variations, the TUE error specification is almost always better that the sum of the individual error specifications.
Note that the TUE error does not take into account the reference errors unless otherwise noted.