Kioxia and Phison spearhead advancements in UFS

Kioxia and Phison are both developing UFS 4.0 fingernail flash cards and controllers, with Kioxia currently sampling its device.

UFS (Universal Flash Standard) cards are used for storage and data transfer in smartphones, digital cameras, tablets, smart TVs, augmented reality and virtual reality headsets, and automotive video and logging applications. The standard was developed to provide faster and higher capacity storage than eMMC (embedded MultiMediaCard) flash. The standard has progressed through several generations, with UFS 4.0 the latest: 

UFS specs

UFS gen 2 and 3 cards are available now with gen 4 cards coming on stream.

Phison is launching a range of UFS controllers to support entry-level, middle, premium, and flagship smartphone devices. The line looks like this:

  • UFS 2.2 PS8327 with 64 GB capacity and the smallest UFS 2.2 controller.
  • UFS 3.1 PS8325 for high-end smartphones, supporting the latest 1 Tb NAND from various manufacturers plus Phison’s 4KB LDPC (Low Density Parity Check) error correction engine. It has secured design wins from many international leading smartphone manufacturers and is expected to start mass production in the first quarter of this year.
  • UFS 3.1 PS8329 for mid-range smartphones. It is the smallest UFS 3.1 controller on the market and is planned to begin sampling in June of this year.
  • UFS 4.0 PS8361 for high-end smartphones with a four-channel design. The highest read and write speeds of PS8361 will exceed 4,000 MB/s. Improved read performance per mA to extend the battery usage efficiency of mobile devices. PS8361 has been designated for use by NAND manufacturers and is expected to begin shipping in the second half of this year.
Samsung UFS card
Samsung UFS card

Kioxia is sampling a UFS 4.0 embedded flash card for automotive applications including telematics, infotainment systems, and ADAS. It says the devices support High Speed Link Startup Sequence (HS-LSS) features, enabling Link Startup (M-PHY and UniPro initialization sequence) between device and host to be performed at a faster HS-G1 Rate A (1,248 Mbps) than that of conventional UFS.

The Kioxia card is available in capacities of 128, 256, and 512 GB, supports a wide temperature range, and meets AEC-Q100 Grade 2 automotive stress test standard requirements.

Samsung, SK hynix, and Micron have all developed UFS 4.0 products. SK hynix is pushing ahead with a UFS 5.0 initiative to double bandwidth to 46.4 Gbps which could mean a maximum 11,600 MBps bandwidth.


UFS implements a full-duplex serial LVDS interface. It supports SCSI Tagged Command Queuing. The standard is developed by and available from the JEDEC Solid State Technology Association. UFS can support higher storage capacities with 1 TB than other storage standards, such as eMMC with 256 GB. eMMC is only able to read and write as separate, asynchronous tasks due to its legacy parallel or half-duplex interface.