Hitachi, Ltd.

Texas Instruments Corporation

Hitachi Vlsi Engineering Corp.

Tetsuya Saeki

Shunichi Sukegawa

Osamu Nagashima

Katsuyuki Sato

Hitoshi Kawaguchi

Yasunori Yamaguchi

Makoto Morino

Yosuke Yukawa

Masahiro Yoshida

Jun Mitake

Terutaka Okada

To provide a type of semiconductor memory device characterized by the fact that the area occupied by the redundant memory address decoder on the chip is minimized without reducing the redundancy of the defective memory, and hence the cost of the semiconductor memory device can be cut. It has both redundant decoders that select the redundant memory in response to the all address bits and the redundant decoders which select the redundant memory group in response to a portion of the address bits, so as to increase the efficiency in saving the defective memory.

Semiconductor memory device and defective memory cell repair circuit

To provide a type of semiconductor memory device characterized by the fact that the redundancy for the defective memory of defective bits is increased and the area occupied by the redundant memory address decoder on the chip is minimized, thereby reducing the cost of the semiconductor memory device. It has multiple fuse decoders which are commonly connected to the address bus and are programmed for the different addresses, and it has a redundant address decoder which detects coincidence/uncoincidence between the outputs of the two decoders and generates a redundant address coincidence signal, so as to increase the efficiency in repairing the defective memory.

A semiconductor memory is provided with a first memory cell group, a second memory cell group, a first register for a serial output operation for holding information related to the first memory cell group, a second register for a serial output operation for holding information related to the second memory cell group, and transfer means for transferring information related to either the first or second memory cell group to either the first or second serial output register. By virtue of this arrangement, while the information transferred to the first serial output register is being serially output therefrom, information can simultaneously be transferred to the second serial output register by the transfer means.

Dynamic ram

Growing community of inventors

Tachikawa, Japan

Tetsuya Saeki