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:
Apr. 11, 2000
Filed:
Jun. 30, 1998
Kazuyuki Yamasaki, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A word level generator in a multiple-valued mask programmable read only memory semiconductor device having a plurality of kinds of mask programmable read only memory cells having a plurality of distributions in number of the mask programmable read only memory cells versus variation of actual threshold voltages from predetermined threshold voltages. The distributions are separated from each other and do not overlap each other. The word level generator generates a word level which is between a maximum voltage level of lower one of adjacent two of the distributions and a minimum voltage level of higher one of the adjacent two of the distributions, so that all of the mask programmable read only memory cells are permitted to show correct ON/OFF operations for application of different word level voltages, whereby only correct data are obtained from the multiple-valued mask programmable read only memory semiconductor device.