US Patent 7561461 Non-volatile semiconductor memory device

In order to determine data stored in a memory cell of a resistive cross-point cell array, two reference cells having two different known resistance values (e.g., data “0” and data “1”) are provided, and a difference in current between a selected cell and the reference cell having data “0” and a difference in current between the selected cell and the reference cell having data “1” are compared. By comparison with a current of the reference cell which has a parasitic current as with the selected cell and has known data “0”/“1”, data can be determined while suppressing an influence of a parasitic current.