The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 16, 2000
Filed:
Jul. 26, 1993
Masaya Kitagawa, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An object of the present invention is that, in a semiconductor memory device having both a redundant circuit and a diagnostic circuit, a memory test for detecting positions of defective memory cells in order to replace the defective memory cells with the redundant circuit can be easily carried out by using the diagnostic circuit. A semiconductor memory device of the present invention includes a normal memory portion, a redundant circuit to replace defective memory cells of the normal memory portion by a units of a word line or a bit line, and a self-diagnostic circuit, and further, in order to realize the object, the device includes a defective cell position storage circuit for storing position information of each defective memory cell when the self-diagnostic circuit detects defective memory cells, and an output circuit for converting position information stored in the defective cell position storage circuit into serial data and outputting the position information.