A semiconductor apparatus includes a reference voltage generation unit, a comparison voltage generation unit, and a calibration unit. The reference voltage generation unit is disposed in a reference die and configured to generate a reference voltage. The comparison voltage generation unit is disposed in a die stacked on the reference die and configured to generate a comparison voltage in response to a calibration control signal. The calibration unit is configured to compare a level of the reference voltage with a level of the comparison voltage and generate the calibration control signal.