MLC-flash cards use pSLC strategy, offer industrial-strength specs

October 25, 2016 // By Graham Prophet
Swissbit's (Bronschhofen, Switzerland) S-46 and S-46u series SD and Micro SD memory cards are intended for applications demanding high endurance and performance. Both products combine the market’s latest MLC flash components with a page based firmware translation layer (FTL) and a single bit per cell storage mode.

The result, Swissbit says, is highest random performance and an endurance that significantly exceeds that of industry standard SD memory cards. The Swissbit S-46 SD memory cards with capacity from 2 GB to 64 GB and S-46u Micro SD memory cards from 2 GB up to 16 GB, work in a storage mode where only a single bit is used per MLC cell. This pSLC mode can be operated much faster than standard MLC mode and increases the permitted program-erase (PE) cycles of MLC from the specified 3k to 20k. Under equal conditions this increases the endurance by a factor of 6.7 at doubled bit cost. In addition the sub-page based FTL allows the firmware to reduce the write amplification to very low values, especially for random writes. Compared to standard industrial SD memory cards the resulting endurance can be up to 600 times greater. The S-46/S-46u cards comply with UHS-I bus mode, up to speed class 10 and offer a sequential data rate close to 50 MB/sec and a random write data rate of up to 1400 IOPS.


These Swissbit products are equipped with read disturb management (RDM) alongside an autonomous, performance-neutral background “auto refresh” process. This type of data care management extends the data reliability especially in read intensive applications. Thanks to the sub-page based management the busy time is kept below the specified limit under all conditions, allowing a high sustained IOPS rate and guaranteeing compatibility with the most widespread industrial and networking SD applications. By using pSLC mode, the protection against data loss during a sudden power fail has also been improved.


The supporting Swissbit life time monitor (SLTM) offers highly detailed status information about the cards and provides a valuable prediction of the expected lifetime allowing for scheduled maintenance.


Swissbit AG;