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:
May. 17, 2005
Filed:
Sep. 26, 2003
Bradley J. Garni, Austin, TX (US);
Thomas W. Andre, Austin, TX (US);
Joseph J. Nahas, Austin, TX (US);
Bradley J. Garni, Austin, TX (US);
Thomas W. Andre, Austin, TX (US);
Joseph J. Nahas, Austin, TX (US);
Freescale Semiconductor, Inc., Austin, TX (US);
Abstract
A circuit provides a stress voltage to magnetic tunnel junctions (MTJs), which comprise the storage elements of a magnetoresitive random access memory (MRAM), during an accelerated life test of the MRAM. The stress voltage is selected to provide a predetermined acceleration of aging compared to normal operation. A source follower circuit is used to apply a stress voltage to a subset of the memory cells at given point in time during the life test. The stress voltage is maintained at the desired voltage by a circuit that mocks the loading characteristics of the portion of the memory array being stressed. The result is a closely defined voltage applied to the MTJs so that the magnitude of the acceleration is well defined for all of the memory cells.