NAND Flash FAQs - KBA222274

Version: *A


What is Cypress' closest suggested migration path from Micron's MT29F (1-2-4 Gb) NAND Flash?

Cypress' closest suggested migration path from MT29Fxx is S34ML-1/S34ML-2 (1-2-4 Gb). However, because ML-1 is EOL, consider replacing it with ML-2 from Q3 2018 onwards. Also, because ML-2 requires 4-bit correction, there is a possibility that it cannot be replaced by a system that can only correct 1 bit.


See the following:


Is the S34ML-2 family series compatible with the Open NAND Flash Interface (ONFI) standard?

Yes. S34ML-2 products are compatible with the ONFI 1.0 specification.

What is the main difference between S34ML-1 and S34ML-2?
The spare area per page size is different. S34ML-1 has a spare area of 64B per 2 KB for all densities, while S34ML-2 has a spare area of 64B per 2 KB for 1G and 128B per 2 KB for other densities.

To migrate from S34ML-1 to S34ML-2, do I need to modify the programming files I have?

Yes. To recognize the larger spare area of S34ML-2, you will need to modify the low-level driver (LLD).

You can download the NAND LLD from the following webpage and use it as a reference for your development:


What is the thermal resistance, Theta JA, Theta JB, and Theta JC of S34ML-2 devices?

We do not provide theta JC and theta JB thermal resistance values for our flash products. We usually give psi JT and theta JA parameters which provide a meaningful method to predict junction temperature in plastic package devices. For Theta JA and psi JT value, see the Device Qualification Report available on our website.


Will the usage of the Spare Area in NAND Flash affect the endurance, data retention, or both of the memory devices?

No. The use of the spare area will not affect endurance, data retention, or both on Cypress NAND flash memory devices. In general, error correction by ECC is required for NAND. Reliability is improved if error correction of more than the error correction bit number specified in the datasheet is performed.

Does Cypress have NAND Flash with on-chip ECC?
No. Cypress does not have NAND devices with on-chip ECC. You can implement 1-bit ECC in your software for S34ML-1, and 4-bit ECC for S34ML-2.