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:
Oct. 03, 2000
Filed:
Jul. 01, 1999
Hitachi, Ltd., Tokyo, JP;
Abstract
A semiconductor memory device is provided which includes a memory cell array, a read circuit which reads data from said memory cell array, and an external terminal which receives an external clock signal. A first input circuit receives the external clock signal and outputs a first internal clock signal delayed from the external clock signal. A second input circuit receives the first internal clock signal and outputs a second internal clock signal delayed from the first internal clock signal. The memory device also includes a circuit which counts a clock signal having a frequency higher than that of the external clock signal and a circuit which starts the counting in response to the second internal clock signal, reverses the direction of said counting in response to the first internal clock signal and detects when a count of said counting circuit again reaches the count at the start of said counting, thereby outputting a timing signal therefrom. A clock output circuit is provided which outputs a third internal clock signal for controlling the operation of said read circuit based on the timing signal.