Embodiments of the disclosure are drawn to apparatuses and methods for scheduling targeted refreshes in a memory device. Memory cells in a memory device may be volatile and may need to be periodically refreshed as part of an auto-refresh operation. In addition, certain rows may experience faster degradation, and may need to undergo targeted refresh operations, where a specific targeted refresh address is provided and refreshed. The rate at which targeted refresh operations need to occur may be based on the rate at which memory cells are accessed. The memory device may monitor accesses to a bank of the memory, and may use a count of the accesses to determine if an auto-refresh address or a targeted refresh address will be refreshed.

A first delay value is obtained by a first memory subsystem of a plurality of memory subsystems. The first memory subsystem performs a first scan operation after a first time from a first event for the first memory subsystem. The first time is based on the first delay value. A second memory subsystem of the plurality of memory subsystems performs a second scan operation based upon a second delay value that is different than the first delay value.

A method for operating a memory is disclosed. The memory includes a first group of word lines, a second group of word lines, a first dummy word line, and a second dummy word line. The first dummy word line and the second dummy word line are between the first group of word lines and the second group of word lines. A first pass voltage is applied to the first dummy word line and applying a second pass voltage to the second dummy word line. A program voltage is applied to a selected word line, wherein a condition is met: a first voltage difference between the first pass voltage and a first threshold voltage of a first dummy cell corresponding to the first dummy word line is different from a second voltage difference between the second pass voltage and a second threshold voltage of a second dummy cell corresponding to the second dummy word line.

NAND memory devices are described that utilize higher read-margin cell types to provide a more granular read disturb indicator without utilizing dummy cells. For example, a NAND architecture may have some cells that are configured as SLC or MLC cells. SLC or MLC cells have more read disturb margin—that is these cells can withstand more read disturb current leakage into the cell before a bit error occurs than TLC or QLC cells. These higher margin cells may serve as the read disturb indicator for a group of cells that have a comparatively lower read disturb margin. Since there are more pages of these higher margin cells than there are pages of dummy cells, these indicators may serve a smaller group of pages than the dummy pages. This reduces the time needed to complete a read disturb scan as fewer pages need to be scanned.

Systems and method for a host-driven data refresh of a Flash memory include registers provided in the Flash memory for storing various settings related to refresh operations, such as, when to start/stop refreshing, target partitions in the memory, target start/end address ranges for refreshing, refresh algorithms, refresh rate requirements, etc. A host can control the various settings for start/stop refreshing, target partitions in the memory, target start/end address ranges for refreshing, refresh algorithms, through the corresponding registers; and the Flash memory can control various values related to refresh rate requirements through corresponding registers. In this manner, a standard platform or interface is provided within the Flash memory for refresh operations thereof.

A processing device in a memory system maintains a counter to track a number of read operations performed on a data block of a memory device and determines that the number of read operations performed on the data block satisfies a first threshold criterion. The processing device further determines whether a number of scan operations performed on the data block satisfies a scan threshold criterion. Responsive to the number of scan operations performed on the data block satisfying the scan threshold criterion, the processing device performs a first data integrity scan to determine one or more first error rates for the data block, each of the one or more first error rates corresponding to a first set of wordlines of the data block, the first set comprising first alternating pairs of adjacent wordlines.

Embodiments herein describe a memory system that includes a DRAM module with a plurality of individual DRAM chips. In one embodiment, the DRAM chips are per DRAM addressable (PDA) so that each DRAM chip can use a respective reference voltage (VREF) value to decode received data signals (e.g., DQ or CA signals). During runtime, the VREF value can drift away from its optimal value set when the memory system is initialized. To address possible drift in VREF value, the present embodiments perform VREF calibration dynamically. To do so, the memory system monitors a predefined criteria to determine when to perform VREF calibration. To calibrate VREF value, the memory system may write transmit data and then read out the test data to determine the width of a signal eye using different VREF values. The memory system selects the VREF value that results in the widest signal eye.

A method includes performing a first operation to program data to a group of memory cells of a memory device, wherein the data comprises host data and a bit pattern indicative of a first temperature of the group of memory cells and receiving a signal to perform a second operation to read the host data from the group of memory cells. The method further includes determining, responsive to receipt of the signal, whether a second temperature of the group of memory cells is outside a threshold temperature differential that is based on the bit pattern indicative of the first temperature of the group of memory cells, applying a voltage offset signal to the group of memory cells responsive to a determination that the second temperature of the group of memory cells is outside the threshold temperature differential, and performing the second operation to read the host data from the group of memory cells subsequent to application of the voltage offset signal to the group of memory cells.

A method includes determining a quantity of refresh operations performed on a block of a memory device of a memory sub-system and determining a quantity of write operations and a quantity of read operations performed to the block. The method also includes determining the block is read dominant using the quantity of write operations and the quantity of read operations and determining whether the quantity of refresh operations has met a criteria. The method further includes, responsive to determining that the block is read dominant and that the quantity of refresh operations has met the criteria, modifying trim settings used to operate the block of the memory device.

A starting read threshold is received. A first offset and a second offset is determined. A first read is performed at the starting read threshold offset by the first offset to obtain a first hard read value and a second read is performed at the starting read threshold offset by the second offset to obtain a second hard read value. A soft read value is generated based at least in part on the first hard read value and the second hard read value.