Mixed current-forced read scheme for MRAM array with selector

A method, comprising:

• forcing a first read current separately through each memory cell of a group of magnetoresistive random access memory (MRAM) cells, including forcing the first read current through an MRAM element and a threshold switching selector of each respective MRAM cell in series;
• comparing, for each respective MRAM cell in the group, a first reference voltage and a second reference voltage to a sense voltage that results across the MRAM cell from forcing the first read current through the MRAM;
• determining a number of the MRAM cells in the group that have a sense voltage between the first reference voltage and the second reference voltage;
• in response to the number being no more than allowed, returning a read result based on comparing, for each respective MRAM cell in the group, a third reference voltage to the sense voltage that results across the MRAM cell from forcing the first read current through the MRAM cell;
• and
• in response to the number being more than allowed:
• performing a self-referenced read of each of the MRAM cells in the group, including forcing a second read current through the MRAM element and the threshold switching selector of each respective MRAM cell in series;
• and
• returning a read result based on the self-referenced read of each of the MRAM cells.

A memory system, the system comprising:

• a cross-point memory array comprising a plurality of first conductive lines, a plurality of second conductive lines, and a plurality of memory cells, each respective memory cell connected between one of the first conductive lines and one of the second conductive lines, wherein each memory cell comprises a magnetoresistive random access memory (MRAM) element and a threshold switching selector connected in series with the MRAM element;
• and
• a control circuit that:
• reads a group of the memory cells using a current-force referenced read in which the control circuit forces a read current through each respective memory cell and samples a voltage that appears across each respective memory cell;
• runs an error correction code (ECC) algorithm on data read from the group using the current-force referenced read;
• returns first decoded data in response to the ECC algorithm successfully decoding the data read from the group using the current-force referenced read;
• performs a self-referenced read of each memory cell in the group in response to the ECC algorithm failing to decode the data read from the group using the current-force referenced read, including forcing a read current through each memory cell in the group;
• runs an ECC algorithm on data read from the group using the self-referenced read;
• and
• returns second decoded data in response to successfully decoding the data read from the group using the self-referenced read.