eMMC vs. SD Cards: A Head-To-Head Comparison

June 16, 2017
By Bethany Dunich

Different types of non-volatile storage media include EEPROM, Solid State Drives (SSD) and NAND-based devices like eMMC and SD Cards – but which solution is the best? This would depend on the application being designed. Form factor, price and performance are a few key attributes that have to be considered when designing one of these solutions into a product. Here is a quick comparison to consider between two storage media options: eMMC and SD Cards.

Overview

eMMC: eMMC, a recent addition to the Panasonic’s Storage Media line, is an embedded type of memory that is not user-removable because it is reflow soldered directly to a PCB.

SD Cards: SD Cards, part of Panasonic’s lineup for quite some time, are designed with high endurance and reliability, and are easily removable.

Performace

eMMC: The contacts on the rear side of the package have a 153 BGA (ball grid array) configuration that reduces unwanted inductance and signal distortion due to the small clearance between chip and board. More specifically, the MC Series (a new series under eMMC) have variable clock frequencies up to 200 MHz, single and dual data transfer rates, and an 8-bit data bus. In simpler terms, one can achieve up to a 280 MB/s read speed and 45 MB/s write speed, depending upon card capacity used. eMMC is also AEC-Q100 certified and undergoes rigorous testing to ensure automotive grade compliance.

SD Cards: Their advantage lies in the ability to be easily removed, for ease of data transfer from one device to another. They also can achieve much greater write speeds than eMMC, depending upon which host device they are being used in and if also UHS-compliant. Theoretically, a UHS-1 U3 rated card should be able to perform up to nearly 104 MB/s write performance given the right circumstances. There are also several NAND options, such as TLC, MLC and SLC types. Security and vibration resistance tends to be more of a concern with SD Cards over eMMC because they are non-embedded. Device data could be accessed by anyone if left unsecured, and excessive vibration can cause pin contacts to be disconnected from the SD connector.

Applications

eMMC: eMMC is most notably used in today’s smartphones as their primary source of internal flash storage. There are, however, many industrial uses for this technology such as automotive infotainment systems, avionics displays, industrial automation/HMI control and many fields that require card longevity but lower cost.

SD Cards: SD cards have a fairly wide range of applications that include but are not limited to, GPS systems, car dash cameras, portable medical monitors (ECG, CPAP), smart utility meters and smart thermostats. Of course, any device with an expandable memory slot can use SD cards for further storage.

Price

eMMC:  eMMC is competitively priced while also maintaining extreme reliability. Cost of an eMMC is subject to card capacity and NAND flash market situation. Prices of NAND flash can increase or decrease accordingly.

SD Cards: SD cards have a broader price range due to the many types of NAND flash used, how robust the controller is, the minimum operating temp, etc. One of Panasonic’s goals is to provide SD Card recommendations tailored to a customer’s use case, which may provide a lower cost.

Form Factor

eMMC:  eMMC has a very small footprint and is a great solution when saving space on a PCB is critical. Panasonic’s embedded media has a 153 BGA pattern (0.5mm pitch), which is becoming an industry standard.

SD Cards: SD cards are available as standard full-size SD or microSD form factors.

In Closing…

It’s difficult to define which technology between the two solutions has a greater advantages, because it’s all based on what the end product or design needs to achieve. A purely read-only application that requires a quick loading time for its operating system may benefit more from an eMMC. A more write-intensive application that logs data each day for several years may benefit more from a SLC type industrial SD card. In any case, Panasonic offers solutions to fit an extremely broad range of applications. For more information on storage media devices, click here.