Kabushiki Kaisha Toshiba

Tohru Furuyama

Junichi Okamura

Natsuki Kushiyama

Kenji Numata

Satoru Takase

Shinji Miyano

Tomoaki Yabe

Yohji Watanabe

Katsuhiko Sato

Takashi Ohsawa

Donald C Stark

Ryo Haga

Kiyofumi Sakurai

Hiroyuki Noji

Shigeo Ohshima

Kiyofumi Ochii

Masataka Matsui

Shigeyoshi Watanabe

Shigeyuki Hayakawa

Tatsuo Ikawa

Hiroto Tanaka

Kazuyoshi Muroka

A dynamic random access memory includes a plurality of dynamic memory cells arranged in rows and columns, a word line connected to the memory cells on the same row, a bit line connected to the memory cells on the same column, a word line selecting circuit having a word line selecting function of selecting an arbitrary one of the rows in response to an internal address signal, a word line driving voltage source, a word line driving circuit having at least one driving MOS transistor connected between the word line driving voltage source and the word line, for driving the word line in response to an output signal of the word line selecting circuit, and a control circuit for, in response to a voltage stress test control signal input from outside, controlling the word line driving circuit so that the word line driving circuit drives word lines more than those selected in a normal operation mode upon receiving an external address signal.

Dynamic random access memory

A semiconductor memory device includes a memory cell having a transfer N-channel MOS transistor and a capacitive element for storing data which is connected to the transfer N-channel MOS transistor, a word line connected to a gate of the transfer N-channel transistor, of the memory cell, a charge pump circuit generating an internal power supply voltage which is boosted up from a power supply voltage, and outputting the internal power supply voltage, and a decoder circuit which receives address signals and has a P-channel MOS transistor for receiving the internal power supply voltage, the decoder circuit generating a word line selecting signal. Also, the semiconductor memory device includes a word line driving circuit for driving a corresponding word line in accordance with the word line selecting signal, the word line driving circuit being provided in correspondence with the word line and having a first MOS transistor and a second MOS transistor, the first MOS transistor having a first current path, a first end of the first current path being connected to a first node having the internal power supply voltage, a second end of the first current path being connected to the word line and a gate which is controlled in accordance with the word line selecting signal, the second MOS transistor having a second current path, a first end of the second current path being connected to the first MOS transistor, a second end of the second current path being connected to a predetermined potential lower than the internal power supply voltage, wherein the charge pump circuit outputs the internal power supply voltage for a first period in which at least the P-channel MOS transistor is in an ON state and a second period in which at least the first MOS transistor is in an ON state.

A semiconductor memory comprises a dynamic type memory cell array arranged to form a matrix and provided with word lines commonly connected to memory cells of respective columns and bit lines commonly connected to memory cells of respective rows, a dummy cell section having a first set of dummy word lines connected to respective complimentary bit line pairs of said memory cell array by way of respective first capacitances and a second set of dummy word lines connected to respective complementary bit line pairs of said memory cell array by way of respective second capacitances, a dummy word line potential control circuit capable of optionally controlling the mode of driving selected dummy word lines when said word lines of said memory cell array are activated and sense amplifiers connected to the respective complementary bit line pairs of said memory cell array for reading data from selected memory cells of the memory cell array onto the related bit line.

Semiconductor memory and screening test method thereof

A dynamic random access memory includes a dynamic memory cell having a transfer N-channel MOS transistor and a capacitive element for storing data which is connected to the transfer N-channel MOS transistor, a word line connected to a gate of the transfer N-channel transistor, of the dynamic memory cell, and a word line driving voltage source, to which power voltage is input for raising the input power voltage to generate a word line driving voltage. Also, the dynamic random access memory includes an address circuit for generating internal address signals in accordance with externally input address signals, a word line selecting circuit for decoding the internal address signals and outputting a word line selecting signal which varies within a range between the word line driving voltage and a ground potential, and a word line driving circuit for driving a corresponding word line in accordance with the word line selecting signal, the word line driving circuit being provided in correspondence with the word line and having a P-channel MOS transistor which has a source connected to a first node having the word line driving voltage, a drain connected to the word line and a gate to which the word line selecting signal is applied.

When data stored in a memory cell of a memory cell array is written into cache memory, a write signal LW is set at an 'H' level. The write signal LW is input into a data-line pair initialization select circuit via an initialization control circuit, and a signal EQE is set at an 'H' level in all columns. A data-line pair initialization circuit then sets the potential of the data-line pairs in all columns at the same level. When the write signal LW is input to a transfer gate via a transfer gate control circuit, the transfer gates in all columns are turned ON. The delay time of the transfer gate control circuit is the same as or greater than the delay time of the initialization control.

Memory circuit with built-in cache memory

A semiconductor memory device includes a memory cell array, row decoder, bit line pairs, sense amplifier, sense amplifier control circuit, data latch, transfer gate, transfer gate control circuit, and write circuit. The memory cell array has dynamic memory cells arranged in an array form. The row decoder decodes a row address signal to select a desired one of rows of the memory cell array. Each of the bit line pairs is connected to those of the memory cells which are arranged on a corresponding one of columns of the memory cell array. The sense amplifier amplifies data read out on the paired bit lines and positively feeding data back to the paired bit lines to hold the data. The sense amplifier control circuit controls the operation of the sense amplifier. The data latch latches readout data and write data. The transfer gate transfers data between the data latch and the sense amplifier. The transfer gate control circuit controls the transfer gate. The write circuit writes data into the data latch in synchronism with a clock signal. At the time of writing data into the memory cells, data is previously supplied to the data latch by the write circuit and latched in the data latch, and after the transfer gate control circuit controls the transfer gate to supply data to the bit line pairs from the data latch, the sense amplifier control circuit activates the sense amplifier.

Clock synchronous type DRAM with latch

Clock synchronous type DRAM with data latch

A semiconductor device comprising a plurality of circuit blocks to which various potentials, including at least one potential either raised or lowered, are assigned. The device further comprises means for selectively and reversely changing the potentials assigned to the circuit blocks.

Semiconductor device and method of screening the same

An improved semiconductor memory device such as a dynamic random access memory (DRAM) includes a latch circuit and an output buffer. The latch circuit latches first data read out from one memory cell of a memory cell array during one cycle of a row address strobe (RAS) signal and during one cycle of a column address strobe (CAS) signal. During another cycle of the row address strobe signal and during another cycle of the column address strobe signal, the first data is transferred from the latch circuit to the output buffer and the latch circuit latches second data read out from another memory cell of the memory cell array. The use of the latch circuit and output buffer reduces access time and increases the data transfer rate of the memory device.

Semiconductor memory utilizing RAS and CAS signals to control the

A semiconductor memory cell of the present invention comprises a cascade gate including a plurality of cascade-connected MOS transistors and having one end connected to a read/write node, and a plurality of capacitors for information storage connected at one end to said MOS transistors, respectively, at the end remote from said node.

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Tokyo, Japan

Tohru Furuyama