In contrast to “raw” NAND flash memory solutions, the e•MMC (Embedded Multimedia Card) and UFS (Universal Flash Storage) devices are able to combine flash memory and the corresponding controller in a single package. By doing this they are able to save space and relieve host processors of key memory management functions including bad block management, error correction, wear levelling and garbage collection.
By doing this the e•MMC and UFS devices are now easier to design in to systems than was the case with standalone memory ICs with a standard NAND Flash interface.
The ‘Supreme+’ e•MMC (JEDEC ver. 5.1) memories are available in capacities from 16GB to 128GB and are based on 15nm MLC NAND flash technology. Sequential read and write speeds of 320MB/s and 180MB/s are around 2% and 20% faster than the read and write speeds of previous devices from Toshiba. Random read and write speeds are also around 100% and 140% better than previous devices.
While e•MMC reaches a theoretical limit with an 8bit parallel interface of 400MB/s, UFS memory extends interface performance through high-speed differential signalling using the MIPI M-PHY interface, offering a theoretical performance of 1166MB/s by supporting a two-lane MIPI M-PHY HS-G3 interface.
The new UFS (JEDEC ver 2.1) devices are also based on 15nm MLC NAND flash technology and can be supplied with capacities from 32GB to 128GB. Compared to previous devices sequential read and write speeds of 850MB/s and 180MB/s represent improvements of around 40% and 16%. Also, random read and write performances are around 120% and 80% better respectively.