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:
Feb. 28, 1989
Filed:
Nov. 12, 1987
Paul D Shannon, Austin, TX (US);
Hiroyuki Oka, Tokyo, JP;
Paul E Grimme, Dripping Springs, TX (US);
Robert W Sparks, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A method and apparatus for post-packaging testing of one-time programmable memories provides means for assuring that each cell of the memory will appear to a customer to be erased and that it is capable of being programmed. The preferred embodiment of the invention is a microcomputer including one-time programmable memory, but the invention also includes memory-only devices. Marginal reading method and apparatus provide for detecting the threshold voltage of memory cells below the level at which the cell appears to the customer to be erased and marginal programming method and apparatus provide for slightly increasing the threshold voltage of cells in order to ensure their programmability.