16869424

Paragraph Number

176

The adjusted read levels align with the changed cell threshold voltage distributions. Were previous read levels, such as previous read level B 708, previous read level E 710, previous read level G 712 used, the memory cells near the boundaries would register data errors. Similarly, because the charge levels of the different memory states A, D, and G have drifted, leaked, been disturbed, or the like by different amounts, and/or in different directions, using the same adjustment for each memory state B, E, and G, in certain embodiments, may register data errors. By configuring the corresponding set of storage cells to use the individually adjusted read levels, the read scan operation may prevent, avoid, or correct potential data errors. In one embodiment, the read scan operation determines the adjusted read levels, adjusted read level B 702, adjusted read level E 704, and adjusted read level G 706, reactively, after a bit error rate crosses a threshold. In another embodiment, the read scan operation determines the adjusted read levels proactively based on operating conditions and media characteristics for a corresponding set of memory cells.

Added by DJM 12 2021