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. 31, 2007
Filed:
Apr. 10, 2006
Shuji Nakaya, Kobe, JP;
Wataru Abe, Hirakata, JP;
Mitsuaki Hayashi, Kyoto, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A semiconductor memory device is provided which has a hierarchical bit line structure and can perform a high-speed read operation even with a low voltage. A subarrayincludes a first MOS transistor PDfor charging a main bit line MBLand a second MOS transistor PSfor charging a sub-bit line SBL. The source electrode of the second MOS transistor PSis connected to a power source voltage, and the source electrode of the first MOS transistor PDis connected via a fourth MOS transistor PDto the power source voltage. Since there is not a resistance between the main bit line MBLand the sub-bit line SBL, which is present if a transistor is used to achieve conduction therebetween, discharging of the main bit line and charging of the sub-bit line can be performed with high speed.