A semiconductor memory device includes a memory region from which first data and second data are sequentially read, and a data output circuit suitable for selectively performing a reset operation on a data pad according to a logical relationship between the first and second data during an output disable period between a first output enable period corresponding to first output data and a second output enable period corresponding to second output data, when sequentially outputting the first and second output data corresponding to the first and second data through the data pad.

The present disclosure relates to a reciprocal quantum logic (RQL) inverter including an inverter bias tap, a pulse generating Josephson junction (JJ), and a superconducting quantum interference device (SQUID) based structure, which includes a SQUID JJ and is connected between the inverter bias tap and the pulse generating JJ. The SQUID based structure is configured to receive an inverter bias signal from the inverter bias tap and receive a data input from a previous circuit stage. When the data input is at logic state “0,” the pulse generating JJ can be triggered so as to provide an output signal with logic state “1.” When the data input is at logic state “1,” the first SQUID JJ can be triggered thereby preventing the pulse generating JJ from be triggered, such that the output signal is provided at logic state “0.”

A semiconductor memory device includes a memory region from which first data and second data are sequentially read, and a data output circuit suitable for selectively performing a reset operation on a data pad according to a logical relationship between the first and second data during an output disable period between a first output enable period corresponding to first output data and a second output enable period corresponding to second output data, when sequentially outputting the first and second output data corresponding to the first and second data through the data pad.