A memory device can sense stored data during memory read operations using a reference trim, and a memory built-in self-test system can perform a multiple step process to set the reference trim for the memory device. The memory built-in self-test system can set a reference trim range that corresponds to a range of available reference trim values and then select one of the reference trim values in the reference trim range as the reference trim for the memory device. The memory built-in self-test system can set the reference trim range by prompting performance of the memory read operations using different positions of the reference trim range relative to read characteristics of the memory device and set a position for the reference trim range relative to the read characteristics of the memory device based on failures of the memory device to correctly sense the stored data during the memory read operations.

Methods, systems, and devices for techniques for retiring blocks of a memory system are described. In some examples, aspects of a memory system or memory device may be configured to determine an error for a block of memory cells. Upon determining the occurrence of the error, the memory system may identify one or more operating conditions associated with the block. For example, the memory system may determine a temperature of the block, a cycle count of the block, a quantity of times the block has experienced an error, a bit error rate of the block, and/or a quantity of available blocks in the associated system. Depending on whether a criteria associated with a respective operating condition is satisfied, the block may be enabled or retired.

A memory performs a sequence of ECS operations to read a codeword, detect and correct any errors, and write the corrected codeword back to the memory array. An ECS circuit counts errors which are detected, and sets a value of one or more ECS registers in a mode register if the count exceeds a threshold filter at the end of the ECS cycle. The memory also includes a forced ECS readout circuit, which responsive to a command, for example from a controller, sets the value(s) in the ECS register(s).

A storage device includes 3D NAND including layers of multi-level cells. Test reads are performed by reading only LSB pages and reading layers in a repeating pattern of reading two and skipping two. A test read of a block is performed when its read count reaches a threshold. The counter threshold is updated according to errors detected during the test read such that the frequency of test reads increases with increase in errors detected. Counter thresholds according to errors may be specified in a table. The table may be selected as corresponding to a range of PEC values including the current PEC count of the 3D NAND. Each table further specifies a number of errors that will result in garbage collection being performed.

A memory device includes a system block for storing test information and includes a data block including memory cells connected to a plurality of low bank column lines and a plurality of high bank column lines. The memory device also includes a column repair controller configured to detect, based on the test information, a concurrent repair column line in which a low bank column line among the plurality of low bank column lines and a high bank column line the plurality of high bank column lines corresponding to the same column address are concurrent repaired.

The present technology includes a memory device. The memory device includes memory cells, page buffers configured to store sensed data obtained from the memory cells, a current sensing circuit configured to compare a sensed voltage generated according to the sensed data and a reference voltage generated according to an allowable fail bit code, and output a pass signal or a fail signal according to a comparison result, and a fail bit manager configured to increase an allowable number of fail bits included in the allowable fail bit code until the pass signal is output from the current sensing circuit, change the allowable fail bit code according to the allowable number of fail bits, and provide the allowable fail bit code to the current sensing circuit.

In one aspect, an apparatus includes a memory repair controller coupled to a memory. The memory repair controller may be configured to provide repair information to cause the memory to disable one or more faulty locations in the memory, and the memory repair controller can be disabled after providing the repair information.

Methods, systems, and devices for selective access for grouped memory dies are described. A memory device may be configured with a select die access protocol for a group of memory dies that share a same channel. The protocol may be enabled by one or more commands from the host device, which may be communicated to each of the memory dies of the group via the channel. The command(s) may indicate a first set of one or more memory dies of the group for which a set of commands may be enabled and may also indicate a second set of one or more memory dies of the group for which at least a subset of the set of commands is disabled. When the select die access mode is enabled, the disabled memory dies may be restricted from performing the subset of commands received via the channel.

A storage system has a memory with a multi-level cell (MLC) block and a partially-bad single-level cell (SLC) block. The storage system repurposes the partially-bad SLC block as a non-volatile read cache for data stored in the MLC block (e.g., cold data that is read relatively frequently) to improve performance of host reads. Because the original version of the data is still stored in the MLC block, the original version of the data can be read if there is an error in the copy of the data stored in the partially-bad SLC block, thus avoiding the need for extensive error-correction handling to account for the poor reliability of the partially-bad SLC block.

Methods, systems, and devices for modifying memory bank operating parameters are described. Operating parameter(s) may be individually adjusted for memory banks or memory bank groups within a memory system based on trimming information. The local trimming information for a memory bank or memory bank group may be stored in a fuse set that also stores repair information for the particular memory bank or in a fuse set that also stores repair information for a memory bank in the particular memory bank group. The local trimming information may be applied to operating parameters for particular memory banks or memory bank groups relative to or instead of global adjustments applied to operating parameters of multiple or all of the memory banks in the memory system.