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. 27, 1999
Filed:
Nov. 25, 1997
Kazumi Kojima, Kasugai, JP;
Toshiya Uchida, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
According to the present invention, there is provided a semiconductor memory device comprising a memory cell array and a redundant memory cell array in which a defective cell in the memory cell array is substituted by a cell in the redundant memory cell array; further comprising: a PROM circuit in which a redundant address corresponding to the defective cell is recorded; a redundant address data holding circuit that holds the data of the redundant address recorded in the PROM circuit on initialisation; a circuit for deciding on redundancy that compares the data held by the redundant address data holding circuit with an address supplied from outside and makes a decision; and a driver circuit for the memory cell array that is actuated in accordance with the result of this decision by the circuit for deciding on redundancy and a driver circuit for the redundant memory cell array. Since a semiconductor memory device as above does not have a PROM circuit that delays the operation in the circuit for deciding on redundancy, high-speed operation of the circuit for deciding on redundancy can be achieved. As a result, overall access time can be reduced.