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. 15, 2001
Filed:
Mar. 30, 2000
Applicant:
Inventors:
Tetsuya Tsujikawa, Hamura, JP;
Atsushi Nozoe, Hino, JP;
Michitaro Kanamitsu, Ome, JP;
Shoji Kubono, Akishima, JP;
Eiji Yamamoto, Kodaira, JP;
Ken Matsubara, Ome, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11C 1/134 ;
U.S. Cl.
CPC ...
G11C 1/134 ;
Abstract
A nonvolatile semiconductor memory device having a plurality of memory cells. Each cell stores data and has a threshold voltage corresponding to the data. A controller controls a partial erase operation in response to a command. This operation includes selecting memory cells in two groups, storing the data in a data latch, writing erase data indicating an erase state, erasing data of selected cells and programming the data stored in the data latch to selected memory cells and programming the erased data to selected memory cells.