In the accuracy specification, does the 'missing codes' figure just refer to cases where the least significant bit doesn't change between angles which differ by 1 lsb.? Does the angular accuracy figure take into account missing codes?
The missing code spec for AD2S80A only applies to 16 bit resolution, it can be up to 4 codes across the full range for particular grades. Your definition is correct i.e. if a missing code occurs the LSB will not change even though the angle has changed. The angular accuracy spec does take into account the missing codes spec.