Abstract: In a normal data reading, one of word lines and one of first and second dummy word lines are selected and data is read out through the access to selected regular memory cell and a reference cell. In a test mode, each of word lines are turned to a non-select state and both of first and second dummy word lines are selected and by setting one of first and second reference voltages to a level different from a level during the normal data reading, data is read out through the access to the reference cells.

Abstract: An internal power supply potential generation circuit includes an overcharge prevention circuit connected to an internal power supply node. The overcharge prevention circuit includes a circuit outputting a signal to be determined that is determined by an internal power supply potential, a differential amplification circuit amplifying a difference in potential between the signal to be determined and a reference potential for output to a node as a signal indicating that current should be drawn, and a current draw circuit drawing current from the internal power supply node in response to the signal indicating that current should be drawn. Thus the semiconductor integrated circuit device of interest can provide a steady internal power supply potential.

Abstract: A logic portion outputs to a DRAM portion a start address and an end address indicating a memory region where data to be stored is present prior to transition to power down mode having reduced current consumption. In the power down mode, a refresh control unit holds the start address and the end address and controls refresh to be carried out for data only in a region requiring refresh. The power supply of the logic portion is set in off state in the power down mode and accordingly a semiconductor device can consume reduced current while holding data.

Abstract: In a shift switch circuit for replacing a data line, a transmission gate circuit connecting node N2 corresponding to ith write data line to node N4 corresponding to ith read data line is provided. An operation of the shift switch circuit can be confirmed according to whether or not an output corresponding to provided data input signal D<i> is observed as data output signal Q<i>. Preferably, a transmission gate connecting i+1th write data line to an output data line is further provided, in order to further ensure operation confirmation. When a fuse circuit is set to replace a data line, ratio of successful chip repairing will be higher.

Abstract: A dummy cell has a plurality of dummy magneto-resistance elements which have the same characteristic as a magneto-resistance element, which characteristic changes corresponding to a voltage applied to the opposite ends. In addition, a voltage applied to opposite ends of each dummy magneto-resistance element is made smaller than a voltage applied to opposite ends of a magneto-resistance element of a memory cell. With this, the dummy cell is designed so as to have an intermediate electric resistance between first and second electric resistances.

Abstract: Each of N memory blocks of first to Nth stages includes a plurality of first and second driver units. The plurality of first and second driver units are respectively provided corresponding to one end and another end of a plurality of digit lines included in each memory block. Each of the first driver units in memory blocks before a selected memory block connects a corresponding digit line to a first voltage according to a voltage level on a digit line of the same row in a memory block of a previous stage. A second driver unit in the selected memory block connects a corresponding digit line to a second voltage in order to supply a data write current. In other words, digit lines in the memory blocks before the selected memory block are not used as current lines but as signal lines.

Abstract: In a shift switch circuit for replacing a data line, a transmission gate circuit connecting node N2 corresponding to ith write data line to node N4 corresponding to ith read data line is provided. An operation of the shift switch circuit can be confirmed according to whether or not an output corresponding to provided data input signal D<i> is observed as data output signal Q<i>. Preferably, a transmission gate connecting i+1th write data line to an output data line is further provided, in order to further ensure operation confirmation. When a fuse circuit is set to replace a data line, ratio of successful chip repairing will be higher.

Abstract: A plurality of bit lines are divided into a plurality of groups each including Y (Y: integer of at least two) bit lines. Y data read data lines passing a data read current therethrough in data reading are provided along with Y connection control parts electrically coupling Y bit lines and the Y read data lines with each other every group. Therefore, the connection control parts electrically connected with the Y read data lines are uniformly divided so that parasitic capacitance applied to the read data lines following electrical connection with the connection control parts can be suppressed. Therefore, the time for charging the read data lines to a prescribed voltage level can be reduced for executing high-speed data reading.

Abstract: In a normal data reading, one of word lines and one of first and second dummy word lines are selected and data is read out through the access to selected regular memory cell and a reference cell. In a test mode, each of word lines are turned to a non-select state and both of first and second dummy word lines are selected and by setting one of first and second reference voltages to a level different from a level during the normal data reading, data is read out through the access to the reference cells.

Abstract: Each memory cell row is associated with access transistors having their source regions electrically connected together by an n+ diffusion node extending in the direction of the row. The n+ diffusion node is connected to a main word line set to have the low level (a ground voltage) in selecting a corresponding memory cell row. When the main word line is set low, responsively in a data read operation a selected row's word line is set high and in a data write operation a selected row's digit line is set high.

Abstract: Each memory cell row is associated with access transistors having their source regions electrically connected together by an n+ diffusion node extending in the direction of the row. The n+ diffusion node is connected to a main word line set to have the low level (a ground voltage) in selecting a corresponding memory cell row. When the main word line is set low, responsively in a data read operation a selected row's word line is set high and in a data write operation a selected row's digit line is set high.

Abstract: Each of N memory blocks of first to Nth stages includes a plurality of first and second driver units. The plurality of first and second driver units are respectively provided corresponding to one end and another end of a plurality of digit lines included in each memory block. Each of the first driver units in memory blocks before a selected memory block connects a corresponding digit line to a first voltage according to a voltage level on a digit line of the same row in a memory block of a previous stage. A second driver unit in the selected memory block connects a corresponding digit line to a second voltage in order to supply a data write current. In other words, digit lines in the memory blocks before the selected memory block are not used as current lines but as signal lines.

Abstract: A plurality of bit lines are divided into a plurality of groups each including Y (Y: integer of at least two) bit lines. Y data read data lines passing a data read current therethrough in data reading are provided along with Y connection control parts electrically coupling Y bit lines and the Y read data lines with each other every group. Therefore, the connection control parts electrically connected with the Y read data lines are uniformly divided so that parasitic capacitance applied to the read data lines following electrical connection with the connection control parts can be suppressed. Therefore, the time for charging the read data lines to a prescribed voltage level can be reduced for executing high-speed data reading.

Abstract: A logic portion outputs to a DRAM portion a start address and an end address indicating a memory region where data to be stored is present prior to transition to power down mode having reduced current consumption. In the power down mode, a refresh control unit holds the start address and the end address and controls refresh to be carried out for data only in a region requiring refresh. The power supply of the logic portion is set in off state in the power down mode and accordingly a semiconductor device can consume reduced current while holding data.

Abstract: A dummy cell has a plurality of dummy magneto-resistance elements which have the same characteristic as a magneto-resistance element, which characteristic changes corresponding to a voltage applied to the opposite ends. In addition, a voltage applied to opposite ends of each dummy magneto-resistance element is made smaller than a voltage applied to opposite ends of a magneto-resistance element of a memory cell. With this, the dummy cell is designed so as to have an intermediate electric resistance between first and second electric resistances.

Abstract: Normal memory cells and dummy cells are arranged continuously in a memory array. In a data read operation, first and second data lines are connected to the selected memory cell and the dummy cell, respectively, and are supplied with operation currents of a differential amplifier. An offset corresponding to a voltage difference between first and second offset control voltages applied from voltage generating circuits are provided between passing currents of the first and second data lines, and a reference current passing through the dummy cell is set to a level intermediate between two kinds of levels corresponding to storage data of a data read current passing through the selected memory cell.

Abstract: During data write, a first driver electrically connects a fist shared node to one of first and second voltages in accordance with write data. A second driver electrically connects a second shared node to the other voltage. A plurality of first switch circuits for electrically connecting one end sides of bit lines to the first shared node, respectively, and a plurality of second switch circuits for electrically connecting the other end sides to the second shared node, respectively, are provided. In accordance with a column select result, the first and second switch circuit for the corresponding bit line are turned on. Therefore, it is possible to execute a data write operation without providing a driver for each bit line.

Abstract: Each of N memory blocks of first to Nth stages includes a plurality of first and second driver units. The plurality of first and second driver units are respectively provided corresponding to one end and another end of a plurality of digit lines included in each memory block. Each of the first driver units in memory blocks before a selected memory block connects a corresponding digit line to a first voltage according to a voltage level on a digit line of the same row in a memory block of a previous stage. A second driver unit in the selected memory block connects a corresponding digit line to a second voltage in order to supply a data write current. In other words, digit lines in the memory blocks before the selected memory block are not used as current lines but as signal lines.

Abstract: In a semiconductor memory device with a plurality of banks having a plurality of memory sub array, according to a mode setting signal, data access control is made depending on whether access is made on a memory sub array basis or a bank basis. A multi-bank semiconductor memory device is provided capable of easily implementing both of a low power consumption mode and a long page size mode.

Abstract: A logic portion outputs to a DRAM portion a start address and an end address indicating a memory region where data to be stored is present prior to transition to power down mode having reduced current consumption. In the power down mode, a refresh control unit holds the start address and the end address and controls refresh to be carried out for data only in a region requiring refresh. The power supply of the logic portion is set in off state in the power down mode and accordingly a semiconductor device can consume reduced current while holding data.