A semiconductor memory device includes a memory cell array having a first group of main blocks, a second group of main blocks and redundancy blocks replacing the first group of main blocks or the second group of main blocks, a repair logic suitable for enabling a replacement signal when one or more of the second group of main blocks are defective, a control logic suitable for generating an address for the second group of main blocks in response to a dedicated command for access to one or more of the second group of main blocks, and an address decoder suitable for selecting one or more of the redundancy blocks based on the address for the second group of main blocks when the replacement signal is enabled.

Semiconductor memory device and method of operating the same

A method for operating a memory (28) that includes a plurality of analog memory cells (32) includes storing data in the memory by writing first storage values to the cells. Second storage values are read from the cells, and a Cumulative Distribution Function (CDF) of the second storage values is estimated. The estimated CDF is processed so as to compute one or more thresholds. A memory access operation is performed on the cells using the one or more thresholds.

Adaptive Estimation of Memory Cell Read Thresholds

A method for decoding a plurality of flash memory cells which are error-correction-coded as a unit, the method comprising providing a hard-decoding success indication indicating whether or not hard-decoding is at least likely to be successful; and soft-decoding the plurality of flash memory cells at a first resolution only if the hard-decoding success indication indicates that the hard-decoding is not at least likely to be successful.

Flash memory apparatus and methods using a plurality of decoding stages including optional use of concatenated BCH codes and/or designation of “first below” cells

A method for operating a memory (28) includes storing data, which is encoded with an Error Correction Code (ECC), in analog memory cells (32) of the memory by writing respective analog input values selected from a set of nominal values to the analog memory cells. The stored data is read by performing multiple read operations that compare analog output values of the analog memory cells to different, respective read thresholds so as to produce multiple comparison results for each of the analog memory cells. At least two of the read thresholds are positioned between a pair of the nominal values that are adjacent to one another in the set of the nominal values. Soft metrics are computed responsively to the multiple comparison results. The ECC is decoded using the soft metrics, so as to extract the data stored in the analog memory cells.

Reading memory cells using multiple thresholds

A method for operating a memory (28) includes storing data in a group of analog memory cells (32) of the memory as respective first voltage levels. After storing the data, second voltage levels are read from the respective analog memory cells. The second voltage levels are affected by cross-coupling interference causing the second voltage levels to differ from the respective first voltage levels. Cross-coupling coefficients, which quantify the cross-coupling interference among the analog memory cells, are estimated by processing the second voltage levels. The data stored in the group of analog memory cells is reconstructed from the read second voltage levels using the estimated cross-coupling coefficients.

Distortion estimation and cancellation in memory devices

A method for operating a memory (24) includes storing data in analog memory cells (32) of the memory by writing respective analog values to the analog memory cells. Identifying an interfered cell having a distortion that is statistically correlated with the respective analog values of the analog memory cells in a set of the analog memory cells. Determining a mapping between combinations of possible analog values of the analog memory cells in the set and statistical characteristics of composite distortion levels present in the interfered memory cell. The mapping is applied to compensate for the distortion in the interfered memory cell.

Estimation of non-linear distortion in memory devices

A method for operating a memory includes encoding input data with an Error Correction Code (ECC) to produce input encoded data including first and second sections, such that the ECC is decodable based on the first section at a first redundancy, and based on both the first and the second sections at a second redundancy that is higher than the first redundancy. Output encoded data is read and a condition is evaluated. The input data is reconstructed using a decoding level selected, responsively to the condition, from a first level, at which a first part of the output encoded data corresponding to the first section is processed to decode the ECC at the first redundancy, and a second level, at which the first part and a second part of the output encoded data corresponding to the second section are processed jointly to decode the ECC at the second redundancy.

Data storage with incremental redundancy

A method for data storage includes initially storing a sequence of data pages in a memory that includes multiple memory arrays, such that successive data pages in the sequence are stored in alternation in a first number of the memory arrays. The initially-stored data pages are rearranged in the memory so as to store the successive data pages in the sequence in a second number of the memory arrays, which is less than the first number. The rearranged data pages are read from the second number of the memory arrays.

Eyal Gurgi

Papers

Adaptive Estimation of Memory Cell Read Thresholds

Distortion estimation and cancellation in memory devices

Estimation of non-linear distortion in memory devices

Data storage with incremental redundancy

Efficient data storage in multi-plane memory devices