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. 12, 1999
Filed:
Apr. 30, 1998
Yuan Tang, San Jose, CA (US);
Chien-Sheng Su, Saratoga, CA (US);
EON Silicon Devices, Inc., Santa Clara, CA (US);
Abstract
There is provided a method of measuring the value of the threshold voltage of a memory core cell in an array of flash EEPROM memory core cells. The memory core cell includes an array core transistor having a corresponding array threshold voltage which is to be measured. There is provided a reference current level at a constant value which is generated by a reference cell transistor having a fixed bias condition and a fixed threshold voltage so that the relationship of the bias voltage applied to its gate and the fixed threshold voltage is linear. A control gate bias voltage applied to the gate of the array core transistor having the array threshold voltage which is to be measured is varied continuously. The varied control gate bias voltage and the reference current level is compared so as to generate a high logic when the varied control gate bias voltage produces a core cell current which is greater than the reference current level to obtain immediately the value of the threshold voltage of the array core transistor.