Abstract: A semiconductor device includes a comparison unit for comparing a resistance value of a memory element selectively connected to an input terminal with a resistance value of a reference resistance, and a resistance reference unit capable of selecting one of a plurality of resistance values and capable of being selectively connected to the input terminal.

Abstract: A semiconductor memory device comprises: a phase change element (RP) and a memory cell transistor (MN0) that controls writing and reading of data with respect to the phase change element (RP); the memory cell transistor (MN0) supplies a current to the phase change element (RP) based on a first potential (VPS) in a first (read) operation mode, and in a second (write) operation mode supplies a current based on the first potential (VPS), and subsequently supplies a current based on a second potential (VPP) higher than the first potential (VPS). In a write operation, consumed current is reduced.

Abstract: A semiconductor device has a plurality of memory cells including memory elements to store information by varying resistance values of the memory elements. The semiconductor device further has a reference system circuit enables measurement of distribution of the resistance values for the plurality of memory cells.

Abstract: A semiconductor memory device includes: plural bit lines connected with plural memory cells, respectively; plural transfer lines allocated in common to the plural bit lines; sense amplifiers (SA1) and (SA2) connected to these transfer lines, respectively; and a control circuit making the sense amplifier (SA2) perform a converting operation during an amplifying operation performed by the sense amplifier (SA1). Because the plural sense amplifiers are allocated to the same bit lines, and these are operated in parallel in this way, data can be read at a high speed.

Abstract: A semiconductor memory device comprises: a phase change element (RP) and a memory cell transistor (MN0) that controls writing and reading of data with respect to the phase change element (RP); the memory cell transistor (MN0) supplies a current to the phase change element (RP) based on a first potential (VPS) in a first (read) operation mode, and in a second (write) operation mode supplies a current based on the first potential (VPS), and subsequently supplies a current based on a second potential (VPP) higher than the first potential (VPS). In a write operation, consumed current is reduced.

Abstract: In a memory readout circuit for use in a phase-change memory device comprising phase-change elements as memory cells, a sense amplifier sets readout voltage, which is applied to a selected phase-change element selected among the phase-change elements by a column selecting switch, to voltage equal to or higher than hold voltage of the selected phase-change element but lower than transition voltage of the selected phase-change element in a readout cycle. The selected phase-change element is read out as a dynamic state in the case where the selected phase-change element is in a set state.

Abstract: A semiconductor device includes a comparison unit for comparing a resistance value of a memory element selectively connected to an input terminal with a resistance value of a reference resistance, and a resistance reference unit capable of selecting one of a plurality of resistance values and capable of being selectively connected to the input terminal.

Abstract: A semiconductor device has a plurality of memory cells including memory elements to store information by varying resistance values of the memory elements. The semiconductor device further has a reference system circuit enables measurement of distribution of the resistance values for the plurality of memory cells.

Abstract: A semiconductor memory device includes: plural bit lines connected with plural memory cells, respectively; plural transfer lines allocated in common to the plural bit lines; sense amplifiers (SA1) and (SA2) connected to these transfer lines, respectively; and a control circuit making the sense amplifier (SA2) perform a converting operation during an amplifying operation performed by the sense amplifier (SA1). Because the plural sense amplifiers are allocated to the same bit lines, and these are operated in parallel in this way, data can be read at a high speed.

Abstract: In a memory readout circuit for use in a phase-change memory device comprising phase-change elements as memory cells, a sense amplifier sets readout voltage, which is applied to a selected phase-change element selected among the phase-change elements by a column selecting switch, to voltage equal to or higher than hold voltage of the selected phase-change element but lower than transition voltage of the selected phase-change element in a readout cycle. The selected phase-change element is read out as a dynamic state in the case where the selected phase-change element is in a set state.