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:
Jun. 28, 2005
Filed:
Jul. 02, 2003
Yasuaki Hirano, Tenri, JP;
Yasumichi Mori, Ikoma, JP;
Shuichiro Kouchi, Tenri, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
In the nonvolatile semiconductor memory device of this invention, a program control circuitsets the threshold value of a first reference cell RFCby means of a write circuit WC on the basis of a result of comparing the threshold value of the first reference cell RFCwith the threshold value of a second reference cell SRC executed by a sense amplifierfor trimming. The compare of threshold values by the sense amplifierfor trimming can be executed within a shorter time than in the threshold value read operation of the first reference cell RFCTherefore, when the number of the first reference cells is increased, the threshold value adjustment time can be remarkably reduced in comparison with the prior art in which the threshold value of the first reference cell is adjusted by reading the first reference cell.