EN27LN51208 Datasheet, PDF (15/46 Pages) Eon Silicon Solution Inc. – 512 Megabit (64 M x 8) SLC, 3.3 V NAND Flash Memory

EN27LN51208
Figure 5. Algorithm for Bad Block Scanning
8.3 Error in Write or Read Operation
Within its lifetime, additional invalid blocks may develop with NAND Flash memory. Refer to the
qualification report for the actual data. The following possible failure modes should be considered to
implement a highly reliable system. In the case of status read failure after erase or program, block
replacement should be done. Because program status fail during a page program does not affect the
data of the other pages in the same block, block replacement can be executed with a page-sized buffer
by finding an erased empty block and reprogramming the current target data and copying the rest of the
replaced block. In case of Read, ECC must be employed. To improve the efficiency of memory space, it
is recommended that the read or verification failure due to single bit error be reclaimed by ECC without
any block replacement. The additional block failure rate does not include those reclaimed blocks.
Write
Read
Failure
Erase failure
Program failure
Up to 4 bits failure
Detection and Countermeasure sequence
Read Status after Erase → Block Replacement
Read Status after Program → Block Replacement
Verify ECC → ECC Correction
Note:
Error Correcting Code → RS Code or BCH Code etc.
Example: 4bit correction / 512 Byte
This Data Sheet may be revised by subsequent versions
or modifications due to changes in technical specifications.
©2013 Eon Silicon Solution, Inc., www.eonssi.com
Rev. A, Issue Date: 2013/09/30