Semiconductor memory device

Abstract

A semiconductor memory device includes a plurality of sense amplifiers for amplifying current changes which occur in corresponding bit line pairs in accordance with binary signals stored in activated memory cells. Each of the sense amplifiers includes first and second current mirror circuits for generating currents of the magnitudes respectively corresponding to currents flowing through a corresponding bit line pair, a storing circuit, responsive to a signal selecting a memory cell, for storing the currents generated by the first and second current mirror circuits before activation of the memory cell, or a difference between these currents, and a current supplying circuit, responsive to activation of the memory cell and based on the amount stored in the storing circuit, for supplying, to the first and second current mirror circuits, currents having a predetermined relationship with the currents having been generated by the first and second current mirror circuits before activation of the memory cell. A current change corresponding to data stored in the selected memory cell and not affected by an offset occurs in a connection node between the first current mirror circuit and the current supplying circuit, or a connection node between the second current mirror circuit and the current supplying circuit.