Is the P/E cycle of MLC really only 3,000 times as its datasheet said?


Firstly, let’s see the conclusion that Renice draw based on the test from Nand Flash test platform NFA100.

1, the P/E cycle of some Block up to 20,000 times in real test, though it said only 3,000 times in datasheet.

2, Each block is an independent individual, and the initial condition of each block is not exactly the same, even though they are the same process in the same production line.

3, No matter it’s original Nand Flash or non-original, they have the necessity of testing, the Nand Flash can be sorted and classified into different levels.

4, Though it is the same Nand Flash chip, the health condition of each Block is not the same

5, The real lifetime (P/E cycle) of Nand Flash may be far greater than its datasheet, only when test, it can play the greater value.

6, Deep understanding of the life performance of Nand Flash in different P/E stages can help better plan ECC.

7, For those who want to convert MLC mode to SLC at a certain stage, when to start conversion is crucial, its RBER corresponding to P/E is the most important reference.

Here is the correlation of P/E and RBER,

Enlarger


The test took 108h and 45 minutes. 





Here is the Renice test process,

1, The selected Block has a discrete distribution and adjacent distribution (2, 3, 1050, 1051)


2, Each Block and the Page of the Block are Pseudo-random number.

3, The next P/E will automatically +1 to the last pseudo-random number to ensure that the pseudo-random number written this time is completely different from the last time.

4, Record the number of bit Errors every 20 P/E times.

5, The interval between Erase and Program is 0

6, 22,960 times of P/E corresponding bit Errors (20*1148=22960) data record took 108 hours and 45 minutes.

7, Renice use Intel MLC Nand Flash (3,000 P/E cycles) for testing.

8, Worksheets are named in decimal, e.g., Block3130 represents Block 3103 (0C1F)

If want to learn more, or interested in Renice NFA100, please email me at may@renice-tech.com.

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