Fujitsu Corporation

Fujitsu Vlsi Limited

Chikai Ohno

Hideaki Suzuki

Hirokazu Yamazaki

Michiyuki Hirata

A redundancy information region having memory cells for retaining relief information indicating the locations of defective memory cells is arranged closer to at least one of a word driver or a plate driver than a memory cell region and a redundancy memory cell region. Since the memory cells of the redundancy information region start operation earlier, a relief/no-relief judgment can be made earlier, allowing reduction in access time. Besides, in memory cell operations, the defective memory cells are deselected in accordance with address information held in a redundancy address region. Redundancy memory cells for relieving the defective memory cells are selected in accordance with the relief information held in a redundancy flag region. Since the redundancy memory cells are selected without using the address information, it is possible to reduce the time that elapses before the redundancy memory cells are selected after the selection of word lines.

Semiconductor memory

A synchronous semiconductor memory device has a noise preventing part for preventing a noise from being transmitted to a memory cell array, where the noise is caused by a change in a write data.

Growing community of inventors

Kasugai, Japan

Chikai Ohno