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:
Mar. 27, 1998
William Schwarz, San Leandro, CA (US);
LSI Logic Corporation, Milpitas, CA (US);
Abstract
A method for testing a memory device which statistically characterizes the failure time for a subset of cells sampled from the memory array before performing testing of the memory array in general. The memory device includes a testing unit which determines the failure times for cells in the sample subset, and a parameter calculation unit which computes one or more statistical parameters from the failure times. These statistical parameters are then used to determine a refresh pause time which is used in a data retention test of the memory array. The testing method may be performed when power is applied to the memory device. Thus, the BIST method may provide for the accurate detection of memory faults in the memory array at any power-up temperature. In addition, the testing method may be performed after the memory array attains an operational temperature, or in response to an operating system command.