High-reliability 3D TLC SSD with Pseudo SLC

UDinfo extend their product portfolio with first 3D NAND Flash modules with pSLC flash. This new cost effective and high reliable storage solutions combines reliability close to SLC with low pricing known from TLC 3D NAND Flash. These modules are dedicated for applications with higher write cycles and capacity requirements.

NAND flash memory is the most popular non-volatile storage element that can be electrically programmed/re-programmed and erased. As technology continuously advances, the demands of greater density and better performance with flash memory become large as well.

Generally NAND flash is categorized in three types – SLC (Single-Level-Cell), MLC (multi-Level Cell) and TLC (Tri-Level Cell). NAND makers have recently announced the latest flash technology – 3D TLC NAND, known as three-bit per cell.

For the demand of Solid-State Drive (SSD) on industrial/ embedded/ military/ medical applications, 3D TLC might not be good enough for high reliability requirements. A method to use its SLC mode, named Pseudo SLC (pSLC), of 3D TLC becomes an option for high program/erase (P/E) cycles and high performance.

The pSLC mode for 3D TLC is only to separate the threshold voltage into two parts and operates as a 1-bit cell:

This kind of operation can speed up the programming time and extend the endurance for single cell.  To implement pSLC on 3D TLC needs only to modify the firmware of SSD controller, which will make the SSD become 1/3 of capacity and extend 10 times of their P/E cycles.  Through the pSLC firmware implementation, SSD becomes high speed and much more reliable for industrial customers.

Conclusion: The pSLC mode can dramatically increase the reliability of SSD with 3D TLC, the most cost-effective NAND.  It makes the SSDs meet high P/E cycle demand in industrial and embedded applications.

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