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:
Oct. 04, 1994
Filed:
Sep. 27, 1993
Michio Nakajima, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A smaller, high-speed, semiconductor memory device having redundancy is disclosed which attains an improved mass productivity. Where a main memory (20) includes a defective memory cell, a defective address designating circuit (21) stores the address of the defective memory cell. Defective address detecting circuits (22a to 22r) detect whether an address signal received at an address signal input terminal (4) coincides with an address signal from the defective address designating circuit (21). If a signal indicative of the coincidence is given to a redundancy memory circuit (23) from the defective address detecting circuits (22a to 22r), data is written in or read from defective address remedy latch circuit groups (23a to 23r) of the redundancy memory circuit (23) which correspond to the defective address detecting circuits (22a to 22r). A data selector (24) selectively outputs data received from the defective address remedy latch circuit groups (23a to 23r) or data received from the main memory (20). Thus, the redundancy memory circuit (23), which requires less space, quickly replaces the defective memory cell of the main memory (20).