A method of programming a nonvolatile memory device including a plurality of memory cells is provided. Each of the plurality of memory cells includes a reversible resistance device. A target memory cell is selected from among the plurality of memory cells. A target resistance state for the reversible resistance device of the target memory cell is determined. A resistance state of the reversible resistance device of the target memory cell is read. The read resistance state is compared with the target resistance state. One of a positive program operation and a negative program operation is performed for the reversible resistance device of the target memory cell when the read resistance state is different from the target resistance state.

An integrated circuit includes a primary memory array with cells switchable between first and second states. The circuit also includes sacrificial memory cells; each fabricated to be switchable between the first and second states and associated with at least one row of the primary array. A controller is configured to detect a write operation to a row of the primary array, stress a sacrificial cell associated with the row and detect a failure of the associated sacrificial cell. The sacrificial cells are fabricated to have lower write-cycle endurance than cells of the primary array or are subjected to more stress. Failure of a row of the primary array is predicted based, at least in part, on a detected failure of the associated sacrificial cell.

A non-volatile memory includes resistive cells, write circuitry, and write detect circuitry. Each resistive cell has a resistive storage element and is coupled to a corresponding first column line and corresponding second column line. The write circuitry is configured to provide a write current through a resistive storage element of a selected resistive memory cell during a write operation based on an input data value. The write detect circuitry is configured to generate a reference voltage using a voltage at the corresponding first column line coupled to the selected resistive memory cell at an initial time of the write operation, and, during the write operation, after the initial time, provide a write detect signal based on a comparison between the voltage at the corresponding first column line coupled to the selected resistive memory cell and the reference voltage, wherein the input data value is based on the write detect signal.

This disclosure relates to selectively performing a read with increased accuracy, such as a self-reference read, from a memory. In one aspect, data is read from memory cells, such as magnetoresistive random access memory (MRAM) cells, of a memory array. In response to detecting a condition associated with reading from the memory cells, a self-reference read can be performed from at least one of the memory cells. For instance, the condition can indicate that data read from the memory cells is uncorrectable via decoding of error correction codes (ECC). Selectively performing self-reference reads can reduce power consumption and/or latency associated with reading from the memory compared to always performing self-reference reads.

Embodiments of the present invention facilitate efficient and effective increased memory cell density configuration. In one embodiment, a memory system comprises: an array of addressable memory cells, wherein the addressable memory cells of the array comprise magnetic random access memory (MRAM) cells and wherein further the array is organized into a plurality of banks; an engine configured to control access to the addressable memory cells organized into the plurality of banks; and a pipeline configured to perform access control and communication operations between the engine and the array of addressable memory cells. At least a portion of operations associated with accessing at least a portion of one of the plurality of memory banks via the pipeline are performed substantially concurrently or in parallel with at least a portion of operations associated with accessing at least another portion of one of the plurality of memory banks via the pipeline.

A method of testing a non-volatile memory (NVM) array includes heating the NVM array to a target temperature. While the NVM array is heated to the target temperature, a current distribution is obtained by measuring a plurality of currents of a subset of NVM cells of the NVM array, each NVM cell of the NVM array is programmed to one of a logically high state or a logically low state, and first and second pass/fail (P/F) tests on each NVM cell of the NVM array are performed. A bit error rate is calculated based on the current distribution and the first and second P/F tests.

This disclosure relates to selectively performing a read with increased accuracy, such as a self-reference read, from a memory. In one aspect, data is read from memory cells, such as magnetoresistive random access memory (MRAM) cells, of a memory array. In response to detecting a condition associated with reading from the memory cells, a self-reference read can be performed from at least one of the memory cells. For instance, the condition can indicate that data read from the memory cells is uncorrectable via decoding of error correction codes (ECC). Selectively performing self-reference reads can reduce power consumption and/or latency associated with reading from the memory compared to always performing self-reference reads.

A memory device for storing data comprises a memory bank comprising a plurality of addressable memory cells and a pipeline configured to process write operations of a first plurality of data words addressed to the memory bank. The memory also comprises a cache memory operable for storing a second plurality of data words and associated memory addresses, wherein the second plurality of data words are a subset of the first plurality of data words, wherein the cache memory is associated with the memory bank and wherein further each data word of the second plurality of data words is either awaiting write verification associated with the memory bank or is to be re-written into the memory bank, and wherein a write verification operation associated with a data word of the second plurality of data words is performed a predetermined period of time after the data word is written into the memory.

A method of programming a nonvolatile memory device including a plurality of memory cells is provided. Each of the plurality of memory cells includes a reversible resistance device. A target memory cell is selected from among the plurality of memory cells. A target resistance state for the reversible resistance device of the target memory cell is determined. A resistance state of the reversible resistance device of the target memory cell is read. The read resistance state is compared with the target resistance state. One of a positive program operation and a negative program operation is performed for the reversible resistance device of the target memory cell when the read resistance state is different from the target resistance state.

A variable resistance memory device includes: a memory cell including a first and second sub memory cell; and a first, second and third conductor. The first sub memory cell is above the first conductor, and includes a first variable resistance element and a first bidirectional switching element. The second sub memory cell is above the second conductor, and includes a second variable resistance element and a second bidirectional switching element. The second conductor is above the first sub memory cell. The third conductor is above the second sub memory cell. The variable resistance memory device is configured to receive first data and to write the first data to the memory cell when the first data does not match second data read from the memory cell.