Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Socionext Inc.

Masakazu Kurata

Mitsuaki Hayashi

Yutaka Terada

Shuji Nakaya

Wataru Abe

Yasuhiro Agata

Kenji Misumi

Tetsuyuki Fukushima

Akifumi Kawahara

Manabu Komiya

Masatoshi Shinagawa

A circuit on an end column of a divided memory array is formed by a block selection transistor having the same shape as that of a memory cell transistor. As the pattern of the connecting section between the main bit line and the sub-bit line is made in the same shape as that of the memory cell, it is possible to realize a pattern uniformity and to eliminate the need for using memory array dummy patterns.

Semiconductor memory device with a selection transistor having same shape and size as a memory cell transistor

In a semiconductor memory device in which each memory cell is constituted by one transistor, in a memory cell pattern, two adjacent bits form one diffusion pattern, two adjacent transistors share a source region, and two drain regions are separated from each other. A plurality of arrays in each of which at least a column of the diffusion patterns is disposed include bit lines, and the bit lines of the first array are independent of the bit lines of the second array. In an interface between the arrays, ends at one side of the bit lines of each of the arrays are located on an associated one of two drain regions which are separated from each other with the source region which is shared on one diffusion pattern sandwiched therebetween. This configuration can provide a sufficient bit-line separation width, and reduce the area.

Semiconductor memory device

In a conventional semiconductor memory device, a replica circuit configured by using a dummy bit line has been unable to charge the dummy bit line to a desired potential due to off leak current. Consequently, the time required for charging or discharging the dummy bit line differs from the desired time, and therefore, it has been unable to set optimum operation timing. To solve these problems, a semiconductor memory device of the present invention includes a dummy memory cell array in which source lines of dummy memory cells are charged simultaneously by a charge circuit configured similarly to a dummy bit line charge circuit, thus suppressing off leak current and performing appropriate timing generation.

A semiconductor memory device includes a memory cell array, a charge circuit which compensates for OFF leakage current developed at selected bit lines, a reset circuit having a ground potential corresponding to a potential at non-selected bit lines, a read circuit constituted by a plurality of transistors whose gates are connected to the bit lines, and a bit line precharge circuit which charges the selected bit lines for a fixed time period. As a result of adopting such a configuration, there is no need to provide a transmission gate, such as a column decoder, to a charging path between the read circuit and the bit lines, so that a low-power supply voltage operation can be effected without the influence of a substrate bias effect.

Semiconductor memory device having bit line precharge circuit controlled by address decoded signals

An output end and an inverted output end of a latch circuit that is connected to an output buffer circuit are switched with each other, and thereby, the relationship between the data of '0' or '1' and the drain of a memory cell is connected or not connected to a bit line is changed. In addition, an input of a sense amplifier is fixed at the grounding potential by means of a test control signal, and thereby, positive logic is confirmed in the case where the output of the output buffer circuit is &#x201c;L,&#x201d; and negative logic is confirmed in the case where the output of the output buffer circuit is &#x201c;H.&#x201d;

Semiconductor memory with a data holding circuit having two output terminals

To provide a nonvolatile memory microcomputer with which a step of testing a microcomputer unit using a logic tester can be omitted, thereby reducing the testing cost. A memory tester supplies test data and expectation data to the nonvolatile memory microcomputer, and the nonvolatile memory microcomputer stores them in a nonvolatile memory. Subsequently, upon receiving an address signal, the nonvolatile memory outputs a test signal and an expectation signal based on test data and expectation data corresponding to the address signal. The test signal is supplied to a circuit block in the microcomputer unit, to drive the circuit block. The circuit block returns a test result signal, which is output to the memory tester together with the expectation signal. The memory tester compares the test result signal and the expectation signal, to judge whether the microcomputer unit operates correctly.

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Osaka, Japan

Masakazu Kurata