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. 27, 1995
Filed:
Mar. 28, 1991
Clinton C Kuo, Austin, TX (US);
Ernest A Carter, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A static RAM includes test features which provide for the detection of soft defects which may cause a defective SRAM cell to behave as a functional DRAM cell. Provision is made for writing either a high or a low logic state to each bit line of the SRAM while not writing any value to its complementary bit line and for sensing the state of each bit line independently of the state of its complementary bit line. In addition, a current test is provided which detects soft defects by means of the increased inverter leakage current caused thereby. It is possible, by properly combining these tests, to reliably detect all soft defects, thereby assuring the data retention capability of the SRAM. This technique avoids the long hold time and/or high temperature test techniques used in the prior art.