M.2, previously known under the name Next Generation Form Factor (NGFF), is an alternative to PCIe Mini Cards (mPCIe) specification of a multi-purpose small-form-factor (SFF) standard for internally mounted computer expansion cards. It has been designed with focus on versatility, smaller footprints and a low power consumption - perfect for portable DAQ needs.
M.2ís flexible specification for physical layout of the board offers multiple card dimensions as well as single- and double-sided modules. Together with its compatibility with a variety of buses, including PCIe 3.0, SATA III, USB 3.0, I2C and many more, M.2 gives system designers great freedom by providing key options to integrate a wide range of device classes such as wireless controllers, mass storage controllers, intelligent I/O controllers as well as data acquisition and signal processing controllers to name a few.
The size of the board can vary from 110mm x 22mm to as little as 12mm x 16mm (in a soldered down version) and the board can have components attached to one or to both of the sides with the lowest specified total thickness of only 2mm. Various miniscule form factors allow for smaller and lighter designs earning M.2 popularity in the mobile computing market.
One of the advantages that M.2 cards have over mPCIe cards is the lower rate of energy consumption, however, there are some cases where more current is required.
Take for example LTE Advanced Category 18 technology, where high-power mode is required for all of the 5 antenna connectors to work properly, making mPCIe a better candidate for the expansion card as it outperforms M.2 by being more reliable and having a lower thermal output in performance mode.
High Data Transfer Rate
The speed fo M.2 devices depends on the number and generation of PCIe lanes being used. To put it in numbers, for 4x PCIe 3.0 lanes M.2 will have a data transfer speed of whopping 3.9GB/s.
M.2 is undoubtedly a large improvement in the area of connectivity by being much faster and more versatile, however, this flexibility also makes card specifications much more confusing. For your convenience, here is a quick explanation of form factor options:
ACCES I/O standard format: TYPE 2280-D3-B-E
Where: 22 - width in mm
80 - height in mm
D3 - thickness, first is a letter denoting a single- (S) or double- (D) sided option, while second character is a number 1, 2 or 3 denoting the maximum allowable thickness
B - is the Key ID that allows designers to determine the device type (card can have keys in more than one position as in the example, B and E)
For a more detailed M.2 specification, visit http://www.pcisig.com/
|8 In/8 Out||Yes||Yes||8SS*||Yes|
|4 In/4 Out||Yes||Yes||4SS*||Yes|
|8 In/8 Out||Yes||Yes||8||Yes|
|4 In/4 Out||Yes||Yes||4||Yes|
|Buf = Buffered I/O Prog = Programmable I/O OPTOs = Optically Isolated * Solid State |
CTRS = Counters/Timers COS = Change Of State Detection = Optionally available RoHS Ready