Apple Inc.
Classifying memory cells to multiple impairment profiles based on readout bit-flip counts

Abstract:

A storage apparatus includes a plurality of memory cells and storage circuitry. The storage circuitry is configured to store a mapping that maps sets of readout bit-flip counts to respective predefined impairment profiles. The impairment profiles specify two or more severity levels of respective impairment types, including read disturb, retention and endurance. Each of the bit-flip counts includes a one-to-zero error count or a zero-to-one error count. The storage circuitry is configured to read data from a group of the memory cells using given readout parameters, to evaluate an actual set of bit-flip counts corresponding to the read data, to classify the group of the memory cells to a respective impairment profile by mapping the actual set of the bit-flip counts using the mapping, and to adapt the readout parameters based on the impairment profile to which the group of the memory cells was classified.