A memory system may include: an error correction code (ECC) generation circuit suitable for generating an M-bit error correction code using N-bit data, where N and M are positive integers; a memory core suitable for storing the N-bit data and the M-bit error correction code; and an ECC circuit suitable for correcting an error of the N-bit data read from the memory core, using the M-bit error correction code read from the memory core, wherein the ECC generation circuit generates the M-bit error correction code using an M×(N+M) check matrix, wherein one column vector among M column vectors corresponding to the M-bit error correction code in the M×(N+M) check matrix has an odd weight, and the other M column vectors have even weights.

A method for testing a memory chip including: performing an electrical die sorting (EDS) test on the memory chip; performing a package test when the EDS test is passed; performing a module test when the package test is passed; performing a mounting test when the module test is passed; and setting the memory chip to a mirroring mode through a fusing operation when the EDS test, the package test, the module test or the mounting test is failed.

A method for testing a memory chip including: performing an electrical die sorting (EDS) test on the memory chip; performing a package test when the EDS test is passed; performing a module test when the package test is passed; performing a mounting test when the module test is passed; and setting the memory chip to a mirroring mode through a fusing operation when the EDS test, the package test, the module test or the mounting test is failed.

Encoders and decoders are provided for memory systems. An encoder scrambles data bits corresponding to a logical page, selected from among multiple logical pages, using a plurality of random sequences, to generate a plurality of scrambled sequences; selects, as an encoded sequence, a scrambled sequence among the plurality of scrambled sequences; and provides a memory device with the encoded sequence to store the encoded sequence in multiple level cells. The selected scrambled sequence has the lowest number of logical high values among the plurality of scrambled sequences.

A method for testing a memory chip including: performing an electrical die sorting (EDS) test on the memory chip; performing a package test when the EDS test is passed; performing a module test when the package test is passed; performing a mounting test when the module test is passed; and setting the memory chip to a mirroring mode through a fusing operation when the EDS test, tire package test, tire module test or the mounting test is failed.

A method for testing a memory chip including: performing an electrical die sorting (EDS) test on the memory chip; performing a package test when the EDS test is passed; performing a module test when the package test is passed; performing a mounting test when the module test is passed; and setting the memory chip to a mirroring mode through a fusing operation when the EDS test, tire package test, tire module test or the mounting test is failed.

A memory circuit may include a plurality of electrically programmable memory cells arranged in an electrically programmable non-volatile memory cell array along a plurality of rows and a plurality of columns, a plurality of word lines, each word line coupled with a plurality of word portions of the plurality of memory cells, each word portion configured to store a data word, and at least one overlay word line coupled with a plurality of overlay portions, each overlay portion including overlay memory cells, each of the plurality of overlay portions including an overlay word. The memory circuit is configured to read, for each of the plurality of word lines, from each of the word portions simultaneously with an overlay portion of the plurality of overlay portions, with an output of the read operation being a result of a logic operation performed on the data word and the overlay word.

A memory circuit may include a plurality of electrically programmable memory cells arranged in an electrically programmable non-volatile memory cell array along a plurality of rows and a plurality of columns, a plurality of word lines, each word line coupled with a plurality of word portions of the plurality of memory cells, each word portion configured to store a data word, and at least one overlay word line coupled with a plurality of overlay portions, each overlay portion including overlay memory cells, each of the plurality of overlay portions including an overlay word. The memory circuit is configured to read, for each of the plurality of word lines, from each of the word portions simultaneously with an overlay portion of the plurality of overlay portions, with an output of the read operation being a result of a logic operation performed on the data word and the overlay word.

A flash memory comprising a first plurality of memory cells, each memory cell of the first plurality of memory cells selectively connected to a first input of a comparator. A second plurality of memory cells selectively connected to a second input of the comparator, wherein a first number of the second plurality of memory cells are in an erased state, wherein a second number of the second plurality of memory cells are in a written state, wherein each memory cell of the first plurality of memory cells and each memory cell of the second plurality of memory cells has a first cell capacitance, and wherein the sum of the first number and the second number is at least three.

A flash memory comprising a first plurality of memory cells, each memory cell of the first plurality of memory cells selectively connected to a first input of a comparator. A second plurality of memory cells selectively connected to a second input of the comparator, wherein a first number of the second plurality of memory cells are in an erased state, wherein a second number of the second plurality of memory cells are in a written state, wherein each memory cell of the first plurality of memory cells and each memory cell of the second plurality of memory cells has a first cell capacitance, and wherein the sum of the first number and the second number is at least three.