Today's fastest and most demanding embedded applications, such as multi-functional smartphones,
PMPs, and tablet computers, require equally capable memory management solutions to provide a rich end-user experience.
Such devices most commonly employ flash memory for content storage.
Typically, flash memory is controlled by a dedicated controller that supervises data reads and writes, and operates under the control of the application's CPU. However, with developments in semiconductor technologies, memory densities are advancing at rapid rates, resulting in memory chips with ever-increasing capacities and making it difficult to keep the controller off the flash memory die. To maintain the required data rates and throughputs for high-density chips designed to store high-resolution video and provide enhanced storage capabilities, the eMMC standard was developed.
eMMC is a standard for embedded memory devices that contain not only a data storage element (such as NAND flash memory), but also a controller for the storage element integrated on the same silicon die. This results in several advantages, such as reduced development time and easier integration of the memory block in the overall system. Ultimately, this leads to a much shorter time-to-market for the end product.
The eMMC solution consists of three components - the MMC (multimedia card) interface, the flash memory, and the flash memory controller - and is offered in the industry-standard BGA package. The MMC System Specification v4.41 and JEDEC BGA packaging standards together define the finer points of the eMMC solution.
The following illustration shows technology areas where eMMC solutions will excel.
Standard-cell library offerings
With interface speeds of up to 52MB/s, configurable bus widths of x1, x4, or x8, and interface voltages of either 1.8V or 3.3V, eMMC is designed to provide fast, reliable, and scalable performance.
The flexibility of the industry-standard architecture of the eMMC solution means that designs for mass-storage applications (such as external HDDs) for portable consumer electronic products are greatly simplified. The eMMC interface design allows a host system to access all major types of mass-storage memory devices, such as embedded memory (eMMC-based memory itself), SD/MMC memory cards, and HDDs (using the "ATA on MMC" specification, making it easier for devices such as mobile handsets containing MMC technology to use the larger capacities of small form-factor hard drives) with a single common MMC Interface Protocol Bus.
Development stages for regular NAND flash-based product
For a product using NAND memory, any changes in the chipset, operating system (OS), or the NAND memory requires changes to be made in the Flash Translation Layer (FTL), which in turn, requires testing the changes at the NAND level, significantly increasing delays for product level testing.
Compared to this, when eMMC is used, intermediate changes need not be tested, since the MMC interface takes care of everything. The following illustration shows the elegance of this solution.
This design also makes it possible to select suppliers for subcomponents from a wider base, which results in increased revenues with lower times-to-market.
The future for eMMC is moving towards its integration and deployment with a new architecture (presently under development) - eMCP. eMMC eliminates the need to develop interface software for all types of NAND memory by integrating the embedded controller into the memory chip and providing an easy-to-use memory solutions package for high-speed data transmissions by devices, such as mobile phones. It also eliminates the need for a memory expansion slot by stacking several memory functions vertically, resulting in a very small footprint for the memory devices.
The following illustration shows how this stack-up works to increase and improve the memory densities of devices.
moviMCP integration with eMMC
As an example, eMCP can be deployed to store the code for an application in the SLC NAND/NOR and DRAM memory, whereas the data can be stored in the eMMC memory in a device.
The latest mobile devices are expected to contain bootable eMMC modules, allowing the device's operating system to partition and format the memory modules as needed, and then boot the device off the modules. Designs are also moving towards a unified, hybrid architecture (supporting both SLC and MLC memory), as illustrated below.
Migration towards a hybrid architecture for SLC and MLC memory
By adopting eMMC, manufacturers stand to significantly gain from simpler and faster product designs, qualification processes, and a much shorter overall time-to-market.
The next illustration shows the BGA packages that Samsung eMMC memory is available in.
Specifications for Samsung's eMMC chips
| Density | Controller | Part Number | Organization | Voltage(V) | Clock Freq | Package | Pack. Size | MMCVer | Status |
|---|---|---|---|---|---|---|---|---|---|
| 2GB | VFX_U | KLM2G1HE3F-B00x | x8 | 1.7~1.95 2.7~3.6 |
Max. 52MHz DDR |
153-ball FBGA |
11.5x13 | eMMC4.41 | MP |
| 4GB | VFX_U | KLM4G1HE3F-B00x | x8 | 1.7~1.95 2.7~3.6 |
Max. 52MHz DDR |
153-ball FBGA |
11.5x13 | eMMC4.41 | MP |
| 8GB | VFX_U | KLM8G2FE3B-B00x | x8 | 1.7~1.95 2.7~3.6 |
Max. 52MHz DDR |
153-ball FBGA |
11.5x13 | eMMC4.41 | MP |
| 16GB | VHX | KLMAG2GE4A-A00x | x8 | 1.7~1.95 2.7~3.6 |
Max. 52MHz DDR |
169-ball BGA | 12x16 | eMMC4.41 | MP |
| 32GB | VHX | KLMBG4GE4A-A00x | x8 | 1.7~1.95 2.7~3.6 |
Max. 52MHz DDR |
169-ball BGA | 12x16 | eMMC4.41 | MP |
| 64GB | VHX | KLMCG8GE4A-A00x | x8 | 1.7~1.95 2.7~3.6 |
Max. 52MHz DDR |
169-ball BGA | 12x16 | eMMC4.41 | MP |
Notes : MP : Mass Production |CS : Customer Sample
Key Features
The key features of Samsung's eMMC memory solutions are summarized in the following table.
| eMMC4.3 | eMMC4.4 | eMMC4.41 | eMMC4.5 | |
|---|---|---|---|---|
| Bus Width | x1/x4/x8 | x1/x4/x8 | x1/x4/x8 | x1/x4/x8 |
| Clock Frequency | ~52MHz | ~52MHz | ~52MHz | ~200MHz |
| Alternative Boot | Yes (optional) | Yes (mandatory) | Yes | Yes |
| Max. Bandwidth | 52MB/s | 104MB/s | 104MB/s | 200MB/s |
| H/W Reset | No | Yes | Yes | Yes |
| DDR Interface | No | Yes | Yes | Yes |
| Multi-Partition | No | Yes | Yes | Yes |
| Enhanced Modes (SLC + MLC) |
No | Yes | Yes | Yes |
| Security Features (Trim, RPMB, Secure Erase, Secure Trim) |
No | Yes | Yes | Yes |
| Secure Trim Refinement | No | No | Yes | Yes |
| High Priority Interrupt | No | No | Yes | Yes |
| Background Operation | No | No | Yes | Yes |
| Packed Command | No | No | No | Yes |
| Cache Handling | No | No | No | Yes |
| Discard | No | No | No | Yes |
| Dynamic Capacity | No | No | No | Yes |
| Sanitize | No | No | No | Yes |
Benefits
The key benefits of using Samsung's eMMC memory solutions include:
-
Ease of use :
Use of the industry-standard eMMC 4.41 interface turns memory accesses into simple read/write operations. Furthermore, the interface eliminates the need to develop separate firmware for the eMMC controller. The interface is flexible and can be configured to operate in either x1, x4 or x8 modes, and runs at either 26MHz or 52MHz. -
Low-cost :
eMMC provides a cost-effective solution and lower development times, resulting in a lower overall time-to-market for your product. The ability of eMMC to be used with both SLC- and MLC-type NAND memory makes it ideal for deployment across any segment, including low-cost legacy chipsets. The latest and revised versions of eMMC are expected to be JEDEC compliant, simplifying designs to great extents. -
Host isolated from changes in NAND memory technology :
The basic design principle of eMMC makes it possible to let technology changes in NAND memory of the end device remain invisible to the host. This significantly reduces the design, development, and testing time for your product, since the Flash Translation Layer (FTL) no longer exists, and does not need to be changed for any NAND-level changes in your product. -
Operation on standard voltage levels:
eMMC memory requires dual power supplies for its operation - a 3.0V (Vcc) for MLC NAND flash, and a 1.8V/3.0V (Vccq) for the controller block. Both these voltage values are standard and available on almost all devices
Applications
The key application areas for Samsung's eMMC memory include:
-
Mobile devices :
Advanced mobile devices and handsets today contain significant computing power and high-end multimedia features, such as high-definition video playback. A significant amount of space is required to store such content, and technologies like eMMC are excellent solutions for such applications. Additionally, eMMC chips (both SLCs and MLCs) are already being used in mobile devices to provide booting functionality. -
Enhanced storage solutions :
Smartphones, tablet PCs, and digital cameras are increasing in their capabilities and are requiring larger density solid state memory that can be easily integrated into system designs. With eMMC, increasing the storage on such devices has become not only simpler, but also cost-effective. -
Replacement for traditional storage media :
Recent trends show that HDDs are slowly being phased out and being replaced by SSDs due to their ever-improving benefits, such as increasing storage densities, reducing costs, and lower power consumption, among others. eMMC's high storage capacity makes it the number one contender as a replacement for traditional storage media.
eMMC is the next big step in memory technology, especially for the mobile platform. Samsung's worldwide technology leadership in memory and expertise in the semiconductor segment will ensure that customers remain ahead at every single step of this exciting journey.
