The most popular mobile storage solution is embedded MultiMediaCard (eMMC). eMMC, a managed NAND flash, is smaller than earlier technologies, making it ideal for small-packaged wearable devices like smartwatches. The components of eMMC are: the eMMC interface, flash memory, and flash memory controller. The components are available from multiple vendors in industry-standard ball grid array (BGA) packages. eMMC uses a discrete controller to hide the complexity of managing the flash memory. By using the eMMC interface, SoC designers benefit from the simplified flash memory interface design and a qualification process that result in reduced time-to-market. Also, the SoC design is future-proofed against the frequent changes in NAND flash component supply and designers can take advantage of faster and less costly eMMC ICs as they become available.
The eMMC interface is designed for low-power devices and implemented mainly in mobile SoCs. It only requires 11 pins to connect to the SoC. The eMMC 5.1 specification allows for fast transfer speeds of up to 400 MB/s, and includes a Command Queuing mechanism used to improve random reads/writes. Samsung’s recently published data highlights the advantages of implementing eMMC:
- Capacities: 4 - 128 GB 
- Sequential R/W: 250/125 MB/s 
- Random R/W: 11,000 / 13,000 IOPS