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. 06, 1997
Filed:
Nov. 08, 1995
Applicant:
Inventors:
Yutaka Hayashi, Kanagawa, JP;
Machio Yamagishi, Kanagawa, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C / ; G11C / ;
U.S. Cl.
CPC ...
3651852 ; 36518503 ; 36518907 ; 365210 ;
Abstract
A rewritable nonvolatile semiconductor memory device having a plurality of memory cells which are electrically and reversably variable in threshold values and one pair of reference cells, provided for each predetermined number of memory cells, having the same cross-sectional structure as the memory cells, the pair of reference cells having written in them data of opposite phases, and, at the time of reading, the currents of the pair of reference cells being combined to produce a reference current and the data being determined by comparing this with the signal current of the memory cell.