Kabushiki Kaisha Toshiba

Katsumi Abe

Masahiro Yoshihara

Shigeo Ohshima

Hiroyuki Ohtake

Haruki Toda

Hiroshi Nakamura

Masaru Koyanagi

Masami Masuda

Toshiaki Edahiro

Naofumi Abiko

Teruo Takagiwa

Hiroyuki Koinuma

Yasuhiro Suematsu

Kaoru Nakagawa

Masahiro Kamoshida

Makoto Takizawa

Nobuo Watanabe

Koichi Magome

Susumu Ozawa

Sibo Ma

Shoichi Ozaki

Yukako Hattori

A semiconductor memory device capable of improving a read characteristic of a sense amplifier and a stored data read method are provided. The semiconductor memory device includes a sense amplifier and a controller. The sense amplifier has a first transistor that clamps a voltage of a bit line, a second transistor that is provided between a voltage node clamped by the first transistor and a reference voltage node, and a third transistor that is inserted between a charge/discharge node and the voltage node clamped by the first transistor. In a first operation mode, the controller turns on the first transistor and the second transistor and turns off the third transistor. In the second operation mode, the third transistor is turned on and in the third operation mode, the first transistor is turned on, the second transistor is turned off, the third transistor is turned on, and the fourth transistor is turned on.

Semiconductor storage device, and method for reading stored data

In general, according to one embodiment, a semiconductor memory device includes a first transistor, a plurality of memory cells and a controller. One end of the first transistor is electrically connected to a first power supply. The plurality of memory cells are electrically connected between other end of the first transistor and a second power supply. The controller is configured to apply a first voltage to a gate of the first transistor when reading data from a selected memory cell. The controller is configured to make the first voltage progressively-increasing.

Semiconductor memory device

A sense amplifier circuit is connected to a bit-line and senses and amplifies a signal read from a memory cell. A first data latch is connected to a sense amplifier via a first bus. A second data latch is connected to a second bus. A plurality of circuit groups are repeatedly provided in a first direction, each circuit group including one sense amplifier circuit and one first data latch. The second data latch is provided between the circuit groups and an input/output buffer.

According to one embodiment, the semiconductor memory includes a memory cell array which includes memory cells to store data, a buffer circuit which includes latches, each of the latches including transistors as control elements and a flip-flop, and a control circuit which turns off the transistors to deactivate one or more of the latches.

Semiconductor memory and semiconductor memory control method

According to one embodiment, a threshold detecting method for detecting threshold values of nonvolatile semiconductor memory cells comprises applying a preset voltage to a word line connected to the memory cells, and performing bit-line sense at two different timings during discharging of one of a bit line connected to the memory cells and a node corresponding to the bit line, while a potential of the word line is kept constant.

Threshold detecting method and verify method of memory cells

According to one embodiment, a semiconductor memory device includes memory cells, holding circuits, and a logical gate chain. The memory cells are associated with columns. The holding circuits are associated with the columns and capable of holding first information indicating whether associated one of the columns is a verify-failed column or not. The logical gate chain includes a plurality of first logical gates associated with the columns and connected in series. Each of the first logical gates outputs a logical level to a next-stage first logical gate in a series connection. The logical level indicates whether the verify-failed column exists or not based on the first information in associated one of the holding circuit. The content indicated by the logical level output from each of the first logical gates is inverted using one of the first logical gates associated with the verify-failed column as a border.

A nonvolatile semiconductor memory device is provided, which includes an input buffer provided with a first inverter that can electrically adjust circuit threshold values, a circuit: threshold value monitor provided with a second inverter having the same circuit configuration as the first inverter to detect the circuit threshold values of the first inverter when the input and output of the second inverter are short-circuited, respectively, a memory storing parameter values that correspond to the circuit threshold values detected by the circuit threshold value monitor, and a data-reader circuit reading the parameter values given to the first inverter from the memory.

Nonvolatile semiconductor memory device

When bit lines or sense amplifiers are checked whether they are defective during a test performed to check whether the bit lines are defectively open, an electrical current supplied from one sense amplifier is detected by another sense amplifier. Thus, if plural bit lines are defectively open, they can be detected simultaneously. Consequently, the test time can be shortened greatly.

A semiconductor memory device includes a memory cell array, a page buffer, a data line pair, a differential amplifier and a precharger. The memory cell array includes a plurality of pages in which a plurality of memory cells are arranged. The page buffer is formed adjacent to the memory cell array, and includes a plurality of sense amplifiers configured to temporarily hold page data read from the memory cells in the page. The data line pair is arranged in the page buffer and is connected to the sense amplifiers. The differential amplifier is configured to amplify a potential difference between lines of the data line pair. The precharger is configured to precharge the data line pair to a predetermined potential. At least one of the differential amplifier and the precharger is formed in the page buffer, and the at least one circuit is electrically connected to the data line pair.

Semiconductor memory device having sense amplifier

A step-down circuit generates a second power supply lower than a first power supply. The step-down circuit includes an output terminal connected to a load circuit, an output transistor connected between the first power supply and the output terminal, and having a gate terminal connected to a first node, a monitor transistor connected between the first power supply and a second node, and having a gate terminal connected to the first node, and a feedback circuit which sets a gate voltage of the output transistor in accordance with a difference between a voltage obtained by dividing a voltage of the second node and a reference voltage. A size of the monitor transistor is changed in accordance with an operation mode of the load circuit.

Step-down circuit

Shunt regions are formed at certain intervals in a memory cell array region as extending in a second direction. The shunt regions each include a contact formed to connect a word line or a signal line wired in the same direction to another metal wire. Extension regions are each formed of an extension of the shunt region in the data cache array region. Data input/output lines extend in a first direction and transfer data on bit lines simultaneously via a data cache array. Sense circuits are arranged around the data cache array and connected to the data input/output lines respectively. The data input/output lines are divided at a certain interval in the first direction. The divided portions are connected to respective leads formed in the extension region in the longitudinal direction thereof and connected to the sense circuits via the leads.

An input data register for latching write data is arranged in a position near a memory cell array of a memory core section. The input data register is arranged on the upstream side of a data path used for writing data into a memory cell. Write data input to a data pin which is arranged in the end position on the downstream side is latched in the input data register via a data input buffer, serial/parallel converting circuit and write data line. Data latched in the input data register is written into a memory cell via a DQ write driver, data line pair, I/O gate and bit line pair in a next write cycle.

Method for writing data to a semiconductor memory comprising a peripheral circuit section and a memory core section including a memory cell

Fast cycle RAM having improved data write operation

A synchronous memory device includes a prefetch address counter. The address counter is composed of an n number of one-bit counter circuits, an n number of adders to which the output signals of these counters are supplied respectively, and an adder control circuit for controlling each adder. A start address is externally supplied to each of the one-bit counter circuits, which in turn count up. When the addressing mode is the sequential mode and the start address is an odd address, each adder performs addition according to the state of the even control signal outputted from the adder control circuit. With the addition, the address outputted from each one-bit counter circuit is inverted, but otherwise the same signal as the address outputted from each one-bit counter circuit is outputted.

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Yokohama, Japan

Katsumi Abe