Patent ID: 6809976
Filing Date: 2004-10-26
Classification: G11C

Abstract:
A non-volatile semiconductor memory device, comprising:a plurality of memory cells each storing data in a non-volatile manner; a reference cell which is compared with a selected memory cell of said plurality of memory cells in read operation; a spare reference cell having same characteristics as those of said reference cell, and provided as a spare of said reference cell; a reference cell selecting section for selecting one of said reference cell and said spare reference cell in said read operation; and a data read circuit for reading storage data of said selected memory cell by comparing access to said one of said reference cell and said spare reference cell which is selected by said reference cell selecting section and access to said selected memory cell, wherein said reference cell selecting section switching selection of said reference cell and said spare reference cell according to one of input and operating conditions, wherein each of said memory cells includes a resistance storage element having an electric resistance according to the storing data and an access element for forming an access path to said data read circuit in accordance with a selection of said memory cells.