Kabushiki Kaisha Toshiba

Hiroshi Sahara

Haruki Toda

Shigeo Ohshima

Koichi Magome

Yuji Watanabe

Hiroyuki Koinuma

Kiminobu Suzuki

Masakazu Kiryu

Shigeo Oshima

Kenji Komatsu

A semiconductor device comprises a plurality of circuits formed on an IC chip area, having electric power systems each being independent, a plurality of power potential supply wires connected to the plurality of circuits, respectively, a plurality of power potential supply terminals connected to the plurality of power potential supply wires, respectively, at least one pad for voltage stress test formed on the IC chip area, and controllers for controlling a predetermined voltage stress to be applied from one of the plurality of power potential supply terminals to all power potential supply wires on the IC chip area by use of an input from the pad for voltage stress test.

Semiconductor device

In a semiconductor memory having a column-direction serial access function, two systems of circuits for selecting and fetching data are provided. A circuit operation is alternately performed such that one system is set up while the other system is accessed, thereby reducing a cycle time for a data selecting/fetching operation.

Serially-accessed type memory device for providing an interleaved data

A semiconductor memory device comprises a memory cell array, a redundant memory cell array, bit line pairs, spare bit line pairs, a column address information storage circuit having stored therein information of a column address of a faulty cell and a column address of a spare cell, column decoders, a first column selecting gate for connecting one of the bit line pairs and first data output line pairs, a second column selecting gate for connecting one of the bit line pairs and a second data output line pair, a spare column decoder for selecting a third or a fourth column selecting line, a third column selecting gate for connecting the spare bit line pairs and the first data output line pairs, a fourth column selecting gate for connecting the spare bit line pairs and the second data output line pair, a first buffer for selecting two data and amplifying and outputting, a second buffer for amplifying and outputting data from the second data output line pair, and a register for storing therein data from the first and/or second buffers.

Semiconductor memory device with column redundancy

In a semiconductor memory system of the serial column access type, a redundant column is used for replacing a defective column. Redundant data lines are connected to the redundant column through a redundant column selection gate. A defective address detection circuit detects the address of a defective column to enable the redundant column selection gate. An address counter is provided for a defective address detection circuit. A redundant column selection circuit selects the redundant column in response to a detection signal from the defective address detection circuit. A data line switching circuit switches, in redundant column select mode, the data lines connecting to a data input/output drive circuit from said regular data lines to the redundant data lines. With this circuit arrangement, in a redundant column select mode, the regular data lines are separated from the data input/output drive circuit. Therefore, even if a shift register constituting a regular column selection circuit operates and the defective column selection gate is enabled to set up a connection of the defective column to the regular data lines, the error data from the defective column is never output. Further, the shift register is operable irrespective of the defective column detection.

Semiconductor memory system

A semiconductor memory device is disclosed which comprises, as shown in FIG. 1, a pair of column lines, memory cells connected to the corresponding column lines, a sense amplifier connected to the column lines, row lines for selecting the memory cells in accordance with a row address signal, and first and second transistors having their current paths connected between the column lines and a fixed potential supply terminal supplied with a positive power source potential or a ground potential, wherein the gates of the first and second transistors are connected to the first and second row lines for a data rewrite operation which can be selected independently of the row line.

Semiconductor memory capable of improving data rewrite speed

This invention discloses an output circuit in an integrated circuit. This invention includes first and second MOS transistors and a drive and control circuit. The first and second MOS transistors are connected in series between Vcc and Vss power source nodes, and receive complementary signals, respectively. When one of the transistors is OFF, and the other transistor is turned off from an ON state, the drive and control circuit moderately decreases a gate potential of the other transistor to a level at which a transconductance of the transistor which is turned off from an ON state is decreased to some extent. Thereafter, the drive and control circuit decreases the gate potential to a level at which the transconductance is sufficiently decreased.

Output circuit of semiconductor integrated circuit

A data transfer circuit is connected between first and second circuits so as to control data transfers therebetween. The data transfer circuit comprises first and second latch circuits for latching data in response to first and second latch control signals, respectively, a first data transfer gate connected between the first circuit and the first latch circuit and responsive to a first gate control signal to make electrical connection or disconnection therebetween, a second transfer gate connected between the first and second data latch circuits and responsive to a second gate control signal to make electrical connection or disconnection therebetween, and a third data transfer gate connected between the second data latch circuit and the second circuit and responsive to a third gate control signal to make electrical connection or disconnection therebetween. After data is transferred from the first circuit to the first data latch circuit, the data can be transferred from the data latch circuit to the second data latch circuit even if the data in the data first circuit disappears. The third data transfer gate can be opened to transfer data from the second data latch circuit to the second circuit.

Serial data transfer circuit for a semiconductor memory device

In a semiconductor memory system of the serial column access type, a redundant column is used for replacing a defective column. Redundant data lines are connected to the redundant column through a redundant column selection gate. A defective address detection circuit detects the address of a defective column to enable the redundant column selection gate. An address counter is provided for a defective address detection circuit. A redundant column selection circuit selects the redundant column in response to a detection signal from the defective address detection circuit. A data line switching circuit switches, in redundant column select mode, the data lines connecting to a data input/output drive circuit from said regular data lines to the redundant data lines. With this circuit arrangement, in a redundant column select mode, the regular data lines are separated from the data input/output drive circuit. Therefore, even if a shift register constituting a regular column selection circuit operates and the defective column selection gate is enabled to set up a connection of the defective column to the regular data lines, the error data from the defective column is never output. Further, the shift register is operable irrespective of the defecting column detection.

For a semiconductor integrated circuit having a data output buffer, separate power source pads and separate reference pads are provided for the data output buffer and the circuit components. Thus, any potential fluctuations or noise generated in the data output buffer are not transmitted to the circuit components, resulting in decreased circuit malfunction.

Semiconductor device having reduced potential fluctuations

A semiconductor memory device determines the level of a select control signal, according to the level of drive signals for two systems as generated in the preceding access cycle, and the level of the least significant bit of an address to fetch data in a desired serial access cycle. In accordance with this select signal, a select circuit selects one of the drive signals as generated by drive signal generating circuits, and supplies the selected signal to two data selecting/fetching systems. The function of this select circuit allows one of the two data selecting/fetching systems to first start the data access operation.

Internal interleaving type semiconductor memory device

In this invention, in a sensing circuit of a dynamic memory, barrier transistors are provided between the bit lines and the sensing amplifier. A circuit is provided that, on sensing and on data transfer, changes the gate potential of the barrier transistors so that during the sensing operation the barrier transistors are temporarily turned OFF, so that sensing can be carried out with high sensitivity, as the sensing system is not affected by the parasitic capacitance of the bit lines, while, on data transfer to the input/output lines, the gate potential of the barrier transistors is raised to a level greater than a value reached by adding the threshold value of the MOS transistors to the power source voltage, so that the conductance of the barrier transistors is increased, thereby speeding up the presensing of the input/output lines in the sensing circuit.

Semiconductor memory having a barrier transistor between a bit line and

A flip-flop circuit has a power terminal set at 5 V, first and second output terminals, a latch section for charging one of the first and second terminals to 5 V and discharging the other one of the first and second terminals to 0 V in accordance with an input signal, a first MOS transistor having a current path connected between the power and first output terminals, a second MOS transistor for charging the gate of the first MOS transistor while the potential of the second output terminal is changed from 5 V to 0 V, and a capacitor for bootstrapping the gate potential of the first MOS transistor to turn on the first MOS transistor. The flip-flop circuit further includes a third MOS transistor, having a current path connected between the gate of the first MOS transistor and the first output terminal and a gate connected to the first output terminal, for charging the gate of the first MOS transistor when the gate potential of the first MOS transistor is dropped a predetermined level in comparison with that of the first output terminal.

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Tokyo, Japan

Hiroshi Sahara