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What Is eMMC? eMMC Storage vs SSD, Explained
Learning Center › eMMC
Learning Center
What Is eMMC? eMMC Storage vs SSD
eMMC (embedded MultiMediaCard) is the storage chip built into many cars, tablets, Chromebooks and machines. It is not a card or a drive you plug in: it is a single chip soldered onto the device's circuit board, holding both the memory and the small processor that manages it.
The key difference
eMMC is soldered to the board.
In plain terms: think of a USB drive or an SD card as a removable bookshelf you can carry away and swap. eMMC is a shelf built into the wall. It is attached permanently to the device's main circuit board at the factory, so there is nothing to plug in, nothing to pull out and nothing that can work loose.
Good
Tough and compact
No slot, no connector and no cable. It keeps working through bumps, vibration and heat, which is why it is used in cars and machines.
Good
Lower cost, lower power
One small chip does the whole job, so devices can be smaller, cheaper and run longer on a battery.
Trade-off
Not upgradeable
You cannot remove or add eMMC later. The storage size is chosen when the device is designed, so buy the capacity you need up front.
For engineers: eMMC is a BGA (ball grid array) package. Solder balls on the underside are reflowed directly onto matching pads on the PCB, so there is no socket and no mating connector to fret or corrode. That gives high shock and vibration tolerance and the smallest footprint, but the part can only be replaced by board-level rework (hot-air removal and re-balling). The footprint (153-ball or 100-ball) and the eMMC version must match the board design, and capacity is fixed at the BOM stage.
The basics
How eMMC storage works.
eMMC is the default storage for compact, low-power and cost-sensitive designs: car infotainment, industrial controllers, point-of-sale terminals, medical devices, IoT gateways and many tablets and Chromebooks.
All in one
Memory plus controller
The NAND flash that stores data and the controller that manages it sit in one package. The controller handles wear leveling, bad blocks and error correction, so the device's main processor does not have to.
Standard
Simple interface
eMMC talks to the processor over an 8-bit parallel bus defined by the JEDEC standard, so the same part works across many processors.
Compare
eMMC vs SSD.
Both store data on NAND flash. The difference is how they are built and where they fit.
| eMMC | SSD | |
|---|---|---|
| Form | One chip soldered to the board | A drive or module you install (2.5", M.2) |
| Interface | eMMC parallel bus | SATA or PCIe NVMe |
| Speed | Up to about 400 MB/s (eMMC 5.1) | About 550 MB/s (SATA) to 14,000 MB/s (PCIe Gen5) |
| Power and size | Very low power, tiny footprint | More power and space |
| Cost | Lower | Higher |
| Replaceable | No, part of the board | Usually yes |
| Best for | Embedded, automotive, industrial, IoT | PCs, servers, high-throughput systems |
Is eMMC as good as an SSD? For a device built for one job, usually yes: it is smaller, cheaper, uses less power and is more rugged. For a computer that moves large files all day, an SSD is faster. See the SSD guide.
Compare
eMMC vs UFS.
Both are flash plus a controller in one chip, soldered to the board. eMMC is a one-lane bridge: it reads or writes, one direction at a time. UFS (Universal Flash Storage) is a two-lane road: it reads and writes at the same time, over faster lanes. A board designed for one cannot take the other.
| eMMC | UFS | |
|---|---|---|
| Data flow | Read or write, one at a time | Read and write at the same time |
| Top speed | About 400 MB/s (eMMC 5.1, HS400) | 1.2 GB/s (UFS 2.1), 2.9 GB/s (UFS 3.1), 5.8 GB/s (UFS 4.1) |
| Typical use | Budget and mid-range devices, Chromebooks, automotive, industrial and IoT | Mid-range and flagship phones, newer automotive, high-performance embedded |
eMMC remains the go-to for cost-sensitive, long-life designs, and will be for a long time. UFS figures are interface maximums; real speeds depend on the part.
eMMC details
Versions and packages.
Versions
eMMC 4.5 / 4.51: HS200 mode, about 200 MB/s, found in older designs.
eMMC 5.0: HS400 mode, about 400 MB/s.
eMMC 5.1: HS400 with enhanced strobe, command queuing for faster small-file work, cache barrier and flush reporting for safer power loss, and secure write protection. The current standard. Newer eMMC generally runs in a design built for an older version, at the older mode.
153-ball vs 100-ball
153-ball is 11.5 x 13 mm at 0.5 mm pitch, the standard footprint for space-constrained designs. 100-ball is 14 x 18 mm at 1.0 mm pitch, used in industrial and automotive boards where larger solder joints matter. Same interface; the difference is fit, not speed. UFS often uses a similar-looking 153-ball package but is not interchangeable.
Choose
Temperature grade and NAND type.
| Grade | Operating temperature | Typical use |
|---|---|---|
| Automotive (AEC-Q100 Grade 2) | -40°C to +105°C | Infotainment, digital clusters, telematics, driver assistance |
| Industrial | -40°C to +85°C | Factory automation, medical, outdoor and surveillance equipment |
| Commercial (extended) | -25°C to +85°C | Consumer and indoor devices, kiosks |
Highest endurance
pSLC
One bit per cell. Pick it for write-heavy data logging.
Balanced
MLC
Balances endurance and cost.
Lowest cost per GB
3D TLC
The most capacity for read-mostly storage.
Built for a long product life. Embedded designs are often built for 5 to 10 years or more. Engineers qualify one part number, so they need it to stay available and unchanged: a fixed bill of materials, a PCN (Product Change Notification) before any change and an EOL (End of Life) notice before a part is discontinued. See BOM Control for how Optima and Optima+ handle this. Cell types are explained in NAND Flash Basics.
Support
eMMC FAQ.
What does eMMC stand for?
Embedded MultiMediaCard. It grew out of the MMC memory card standard and is maintained by JEDEC.
Can I upgrade or replace eMMC?
Not in normal use. eMMC is soldered to the circuit board, so the capacity is set when the device is made. Adding storage means using a card slot or USB port if the device has one.
Is eMMC RAM?
No. eMMC is storage that keeps data with the power off. RAM, such as DDR memory, is working memory that is cleared at power off.
Is eMMC outdated?
No. eMMC 5.1 remains the standard for automotive and industrial boards because of its long supply lifecycle, low cost and simple integration. UFS is faster but is aimed mainly at phones.
Designing with eMMC?
Centon Electronics supplies eMMC 5.1 in automotive, industrial and commercial grades, with long-lifecycle supply and engineer-to-engineer support. Ask for samples and datasheets.
Or call 800-234-9292, Monday to Friday.We’re here to help! Reach out to us with your inquiries, feedback, or support needs. Our team is ready to assist you.
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