U.S. patents available from 1976 to present.
U.S. patent applications available from 2005 to present.

Semiconductor memory device having redundancy circuit portion

Patent 4757474 Issued on July 12, 1988. Estimated Expiration Date: Icon_subject January 21, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

Fault-tolerant cell addressable array
Patent #: 4051354
Issued on: 09/27/1977
Inventor: Choate

Defect tolerant memory Patent #: 4380066
Issued on: 04/12/1983
Inventor: Spencer ,   et al.

Inventors

Application

No. 07/011268 filed on 01/21/1987

US Classes:

365/189.07, Including signal comparison365/200, Bad bit365/210, Reference or dummy element365/230.03, Plural blocks or banks714/710Replacement of memory spare location, portion, or segment

Examiners

Primary: Fears, Terrell W.

Attorney, Agent or Firm

International Class

G11C 29/00 (20060101)

Foreign Application Priority Data

1986-01-28 JP

Abstract

A semiconductor memory device includes a redundancy circuit having upper address bit input terminals receiving upper address bit, lower address bit input terminals receiving lower address bits, a regular memory cell array having a plurality of word lines and bit lines, and a plurality of memory cells are arranged at each intersection of the word and bit lines. A redundancy memory cell array is provided having a plurality of word and bit lines, and a plurality of memory cells are arranged at each intersection of the word and bit lines. The capacity of the redundancy memory cell array being smaller than the regular memory cell array. A first selection circuit selects a word or bit line in the regular memory cell array in accordance with the upper and lower address bits. A second selection circuit select a word or bit line in the redundancy memory cell array in accordance with the lower address bits. A redundancy address programming circuit programs the upper address bits corresponding to defective memory cells in the regular memory cell array. A control circuit compares the input upper address bits with the programmed upper address bits and controls the first and second selection circuits to inhibit the selection of the word or bit lines in the regular memory cell array. A predetermined word or bit line in the redundancy memory cell array is selected therefor when each of the input upper address bits coincides with each of the programmed upper address bits.

Other References

  • Bipolar-Transistor Type Semiconductor Memory Device Having Redundancy Configuration, Tomoharu Awaya et al., U.S. Ser. No. 788,587, filed 10/17/85
  • Bipolar-Transistor Type Random Access Memory Device Having Redundancy Configuration, Isao Fukushi et al., U.S. Ser. No. 788,458, filed 10/17/85
PatentsPlus Images
Enhanced PDF formats
loading...
PatentsPlus: add to cart
PatentsPlus: add to cartSearch-enhanced full patent PDF image
$9.95more info
PatentsPlus: add to cart
PatentsPlus: add to cartIntelligent turbocharged patent PDFs with marked up images
$18.95more info
 
Sign InRegister
Username  
Password   
forgot password?