a voltage generator suitable for measuring an internal temperature of the memory device and generating a temperature voltage that has a voltage level determined according to the internal temperature and a reference voltage that has a constant voltage level independent of a change in temperature;

a code generator suitable for generating an initial code based on the temperature voltage and the reference voltage; and

a code calibrator suitable for generating a calibrated code based on the initial code and a calibration factor,

wherein the calibrated code is generated by performing a gain calibration and an offset calibration,

wherein the code generator performs the gain calibration to generate the calibrated code such that a generation range of the calibrated code corresponds to a predetermined temperature range, and

wherein the code generator performs the offset calibration to generate the calibrated code such that the calibrated code generated at a first temperature corresponds to a first target code predetermined according to the first temperature.