A memory device includes a high density or 3D data memory and a 3D reference memory. The reference memory is used to generate a reference signal used to sense data in the data memory. Conversion circuitry converts signals from one memory cell or a group of memory cells in the reference memory into a reference signal. The reference signal is applied to a sense amplifier to sense data stored in a selected memory cell in the data memory.

Disclosed are methods, systems and devices for generation of a read signal to be applied across a load for use in detecting a current impedance state of the load. In one implementation, a voltage and current of a generated read signal may be controlled so as to maintain a current impedance state of the load.

Adaptive read threshold voltage tracking techniques are provided that employ bit error rate estimation based on a non-linear syndrome weight mapping. An exemplary device comprises a controller configured to determine a bit error rate for at least one of a plurality of read threshold voltages in a memory using a non-linear mapping of a syndrome weight to the bit error rate for the at least one of the plurality of read threshold voltages.

A memory system includes a nonvolatile memory which comprises a plurality of memory cells capable of storing 4-bit data represented by first to fourth bits by sixteen threshold regions, and a memory controller configured to cause the nonvolatile memory to execute a first program for writing data of the first bit, the second bit, and the fourth bit and then causes the nonvolatile memory to execute a second program for writing data of the third bit. In fifteen boundaries existing between adjacent threshold regions among the first to sixteenth threshold regions, a maximum value of the number of first boundaries used for determining a value of the data of the first bit, the number of second boundaries used for determining a value of the data of the second bit, the number of third boundaries used for determining a value of the data of the third bit.

Methods, systems, and devices for storing and reading data at a memory device are described. A memory device may utilize one or more storage states to store data within a data word. The memory device may exhibit higher data leakage or more power consumption when storing or reading a first storage state compared to storing or reading one or more other storage states. In some cases, the memory device may generate a second data word corresponding to a first data word by modifying each symbol type of the first data word to generate a different symbol type for the second data word. A memory device may reduce the occurrence of a storage state associated with large data leakage, or high-power consumption, or both. Further, the memory device may generate and store an indicator indicating the transformation of a corresponding data word.

Some embodiments include apparatuses and methods of using the apparatuses. One of the apparatuses includes a substrate, a first deck including first memory cell strings located over the substrate, a second deck including second memory cell strings and located over the first deck, first data lines located between the first and second decks and coupled to the first memory cell strings, second data lines located over the second deck and coupled to the second memory cell strings, and first and second circuitries. The first and second data lines extending in a direction from a first portion of the substrate to a second portion of the substrate. The first buffer circuitry is located in the first portion of the substrate under the first memory cell strings of the first deck and coupled to the first data lines. The second buffer circuitry is located in the second portion of the substrate under the first memory cell strings of the first deck and coupled to the second data lines.

A memory sub-system configured to: measure a plurality of sets of signal and noise characteristics of a group of memory cells in a memory device; determine a plurality of optimized read voltages of the group of memory cells from the plurality of sets of signal and noise characteristics respectively; generate features from the plurality of sets of signal and noise characteristics, including at least one compound feature generated from the plurality of sets of signal and noise characteristics; generate, using the features, a classification of a bit error rate of data retrievable from the group of memory cells; and control an operation to read the group of memory cells based on the classification.

A memory device to program a group of memory cells to store multiple bits per memory cell. Each bit per memory cell in the group from a page. After determining a plurality of read voltages of the group of memory cells, the memory device can read the multiple pages of the group using the plurality of read voltages. For each respective page in the multiple pages, the memory device can determine a count of first memory cells in the respective page that have threshold voltages higher than a highest read voltage, among the plurality of read voltages, used to read the respective page. The count of the first memory cells can be compared with a predetermined range of a fraction of memory cells in the respective page to evaluate the plurality of read voltages (e.g., whether any of the read voltages is in a wrong voltage range).

Memory having a controller configured to cause the memory to determine a respective raw data value of a plurality of possible raw data values for each memory cell of a plurality of memory cells, count occurrences of each raw data value for a first set of memory cells of the plurality of memory cells, store a cumulative number of occurrences for each raw data value, determine a plurality of valleys of the stored cumulative number of occurrences for each raw data value with each valley corresponding to a respective raw data value of the plurality of possible raw data values, and, for each memory cell of a second set of memory cells of the plurality of memory cells, determine a data value for that memory cell in response to the raw data value for that memory cell and the respective raw data values of the plurality of valleys.

A controller includes memory and a microcontroller coupled to the memory. The memory is configured to store a list of entries of data in Flash memory coupled to the controller. The microcontroller is configured to periodically update the list of entries based on data programmed into the Flash memory, and check the list of entries upon reading data from the Flash memory.