Sandisk changes the NAND and keeps the e.MMC interface

Sandisk has introduced the iNAND CL EM181 at electronica, giving manufacturers a way to move to newer NAND without changing the e.MMC interface. The 64 GB, 128 GB and 256 GB versions all use an 11.5 × 13 mm JEDEC-compatible package, which keeps the migration manageable for products such as gateways and cameras that may stay in production for years.

How the drive handles writes is likely to matter more in those designs than the move to newer NAND on its own. Sandisk’s SmartSLC feature allocates some blocks to operate in single-level cell mode as part of the drive’s write handling. The separately configurable Enhanced User Data Area is a true SLC partition, according to Sandisk, so the host can give frequently rewritten data a dedicated region rather than treating the whole drive as one pool.

Sandisk’s internal tests put sequential read and write speeds at up to 300 MB/s and 225 MB/s respectively. The rated temperature range is −25 °C to +85 °C, with LDPC error correction, automatic refresh and power protection listed.

The useful distinction is between a write burst and the same write rate held for hours. A gateway may cope with a short burst during start-up and still fall behind when logs arrive faster than the drive can clear them. A dedicated SLC area makes it possible to isolate that traffic, but it takes capacity away from the general storage pool. The release gives peak sequential speeds rather than steady-state results for that partition, and it doesn’t say how long a given logging workload can be sustained.

Sources: Sandisk announcement