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:
Jul. 12, 1988
Filed:
Apr. 03, 1987
John P Hayes, Ann Arbor, MI (US);
Younggap You, Ann Arbor, MI (US);
The University of Michigan, Ann Arbor, MI (US);
Abstract
Very large dynamic RAM integrated circuits are rendered self-testing by using on-chip generation of data test patterns with very high fault coverage, and concurrent testing of storage cell subarrays to reduce overall testing time. A test generator, which may operate in combination with the refresh control and timing system of the RAM integrated circuit, supplies the initial data test pattern which is loaded into the storage arrays. The conventional sense amplifier array is modified, and coupled with a gate control system for shifting data in each column of each storage subarray to an adjacent column. Alternatively, a two-terminal bilateral storage cell may be used to effect the shifting function, which effectively converts the memory into a shift register. The use of complementary data test patterns will permit detection of symmetrical faults within storage arrays.