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. 01, 1999
Filed:
Sep. 22, 1997
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A system for testing and adjusting threshold voltages in flash EEPROMs is disclosed. The system includes a memory cell array (5) comprising a plurality of cell columns. Each cell column includes a plurality of memory cells (10). Each memory cell (10) has a control gate terminal (14), a drain terminal (12) and a source terminal 11. A control system comprising a wordline decoder (16), a column decoder (19) and a microprocessor (21) applies selected voltages to the respective terminals of the memory cells (10), and selects one of the plurality of cell columns for compaction verification. A detector (30) determines whether any one of the memory cells (10) of the selected cell column has a threshold voltage below a predetermined positive voltage, and supplies an output signal to the control system. The control system increases respective threshold voltages of the memory cells (10) of the selected cell column in response to the output signal of the detector (30).