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. 23, 2001
Filed:
Sep. 21, 2000
Applicant:
Inventors:
Assignee:
Rohm Co., Ltd., Kyoto, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C 1/604 ;
U.S. Cl.
CPC ...
G11C 1/604 ;
Abstract
The same information is stored in two memory cells (,and,′) and the two memory cells are connected in parallel (OR) at a normal reading to synthesize an electric current in conformity with information in the two memory cells. Even if a floating gate and drain are shorted with each other in a storage transistor in one of the memory cells when a tunnel oxide film is deteriorated, destroyed or shorted by a high-tension stress, the discriminating voltage of a sense amplifier is determined so as to ensure normal reading of information in the other memory cell. The two memory cells are separated at test-reading for independent operations to ensure individual testing each memory cell.