US Patent 7423914 Data output device and method of semiconductor device

The data output device comprises a first comparator for comparing first output data with arbitrary output data on a bit-by-bit basis and outputting a first pre-flag signal, a second comparator for comparing second output data with the first output data on a bit-by-bit basis and outputting a second pre-flag signal, a first logic unit for performing a logic operation with respect to pre-flag signal and an arbitrary data inversion flag signal and outputting a first data inversion flag signal, a second logic unit for performing a logic operation with respect to the second pre-flag signal and the first data inversion flag signal and outputting a second data inversion flag signal, a first repeater for inverting or non-inverting and outputting a plurality of bits contained in the first out put data, and a second repeater for inverting or non-inverting and outputting a plurality of bits contained in the second output data.