The XFM standard is intended to combine the advantages of M.2 SSDs and BGA SSDs. Kioxia is now launching the flash memory form factor, reminiscent of a memory card, for compact laptops, IoT devices and in-vehicle applications.
The New Crossover Flash Memory (XFM)
The abbreviation XFM stands for Cross (X) Over Flash Memory and was created with the specification JEDEC XFM 1.0 Device was declared the official storage standard last year. The driving force behind this is JEDEC member Kioxia, who about three years ago, then as Toshiba Memory, described a new form factor for small flash memory modules including a suitable slot under the XFMExpress brand. .
At first glance, the 14 × 18 × 1.4 mm (L × W × H) memory module with an area of 252 mm² is reminiscent of a 11 × 15 × 1.0 mm (L × W × H) microSD memory card ) but is even more compact. The 1.4mm height matches the miniSD form factor. The mini memory can hide behind a 1 euro coin.
XFMExpress (Photo: Kioxia) However, XFMExpress is actually a new SSD form factor for monoblock models. So far, Kioxia has served this field with SSDs such as the BG4 series, which measure 22×30mm (L×W) as a pluggable M.2 SSD or in a 16×20mm (L×W) BGA package. W) soldered directly to the motherboard. XFMExpress aims to combine the compactness of BGA with the flexibility of M.2. The modular design with base (2.2mm high) offers the advantages of expandability and repairability, which accumulates advantages in terms of durability.
Figure 1 of 7 PCI Express is used as an electrical interface, supporting one, two, or (optionally) four lanes (lanes) of the PCIe 3.0 and PCIe 4.0 standards. This translates to raw data rates of nearly 1 GB/s (1 lane), 2 GB/s (2 lanes) and 4 GB/s (4 lanes) over PCIe 3.0, twice the data rate for PCIe 4.0. In the future, PCIe 5.0 will be supported with doubled data rates.
The first products
It is not surprising that Kioxia also manufactures the first products based on the XFM standard. The Kioxia XFMExpress XT2 series includes 256 GB and 512 GB of memory; was previously promised up to 1TB. Removable storage uses PCIe 4.0 x2 for just under 4GB/s raw. The net data rate can be a maximum of 3.5 GB/s but ultimately depends on the NAND flash and controller used. However, no information is available on these latter components. Kioxia describes the key features of XFMExpress XT2 as follows:
- High maintainability – The XFMEXPRESS XT2 enables a new class of small storage devices that are easy to maintain and expand. Combining a rugged and compact body, removable storage functionality and flexibility, the XFMEXPRESS XT2 helps overcome technical barriers and design limitations.
- Ideal for mobile devices – The JEDEC XFM DEVICE 1.0 form factor takes up only 252 square millimeters with its small size and low profile (14mm x 18mm x 1.4mm).  It takes up space and optimizes space when integrated into ultra-compact host devices without sacrificing performance or serviceability. With a minimum device height of just 1.4 millimeters, the XFMEXPRESS XT2 is ideal for thin and light laptops and opens up new design possibilities for next-generation applications and systems.
- couple – Designed for speed, the XFMEXPRESS XT2 features an interface with PCIe 4.0 x 2 lanes and NVMe 1.4b. The leading industry  The storage device’s performance and rugged form factor provide an attractive alternative to other SSD form factors (such as M.2) and enable high-quality computing and entertainment experiences.
Kioxia plans to showcase the XFMExpress XT2 at Embedded World 2022 in Nuremberg (June 21-23) and Flash Memory Summit (August 2-4) in California. The press release already talks about the market launch. However, finished concrete products that use the new standard are not listed.
She works as a writer at Research Snipers.