Semiconductor memory apparatus, semiconductor system and method of sensing data

PURPOSE: A semiconductor memory device, a semiconductor system, and a data sensing method are provided to reduce an error by controlling a voltage level of a read bias signal. CONSTITUTION: A data reading unit(220) senses data of a memory block based on voltage levels of a plurality of read bias signals and outputs the sensing result as output data. A read bias control unit(130) compares a plurality of first data counting codes with a plurality of second data counting codes and outputs a bias control code with a code value corresponding to a comparison result. A read bias generating unit(230) generates the plurality of the read bias signals whose voltage levels are controlled according to the code value of the bias control code.