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:
Nov. 14, 1995
Filed:
Jul. 18, 1994
Kazuyuki Miyazawa, Iruma, JP;
Katsuhiro Shimohigashi, Musashimurayama, JP;
Jun Etoh, Hachiohji, JP;
Katsutaka Kimura, Sagamihara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In an address multiplexed dynamic random access memory (RAM) which has both a normal operation mode and a test mode capability, the test mode is initiated in response to particular signal level combinations of both the row address strobe (RAS) and column address strobe (CAS) signals and the write enable (WE) signal. Since the signal level combinations employed in connection with implementing the test mode are unused in the normal operating mode of the dynamic RAM, additional external terminals are unneeded. This dynamic RAM employs multiplexing circuitry on both the input side as well as on the output side of the dynamic RAM, which multiplexing circuitry is controlled during normal operation by select signals from a decoder and during the test mode by a test signal which allows accessing of data at all of the common complementary data lines by the testing circuitry so as to determine whether there is consistency or inconsistency of the data being read out for testing.