UFS

UFS – Universal Flash Storage is a drive specification for smart phones, digital cameras and similar devices. It’s the size of a (very) large fingernail and replaces earlier eMMC and SD card specifications. For example, a Micron UFS 4.0 card is 11 x 12mm in size with an extended one coming 9 x 13mm in size. UFS is SCSI-based, supports SCSI tagged command queuing and the standard is looked after by JEDEC. The JEDEC UFS standard refers to both embedded memory storage and removable memory cards.

Here is a table showing how the standard has developed;

Micron is building an extended UFS 4.0 card with more speed and SK hynix is developing a UFS 5.0 card. As of October 2025, JEDEC is developing a UFS 5.0 standard designed for mobile applications and computing systems that demand high performance with low power consumption. UFS 5.0 plans to deliver faster data access and improved performance compared to its predecessor, while maintaining compatibility with UFS 4.x hardware. It will include the following and other features:

• Inline Hashing for greater security
• Increased sequential performance up to 10.8 GB/s to meet AI demands
• Integrated link equalization for more reliable signal integrity
• Distinct power supply rail to provide noise isolation between PHY and memory subsystem, easing system integration

JEDEC UFS leverages specifications from the MIPI Alliance to form its Interconnect Layer. This collaboration continues with UFS 5.0, which leverages the upcoming MIPI M-PHY version 6.0 specification and the UniPro version 3.0 specification. M-PHY 6.0 introduces a new High-Speed Gear 6 (HS-G6), which supports data rates double those of the previous maximum data rate of HS-G5, enabling UFS interface bandwidth of 46.6 Gb/s per lane and supporting up to ~10.8 GB/s effective read/write operation for UFS 5.0 over 2 M-PHY lanes.

SD Express and UFS

UFS and SD Express are advanced storage technologies designed for high-performance applications, but they differ in form factor, use cases, and technical specifications.

• UFS: A high-speed flash storage standard developed by JEDEC, primarily used in smartphones, tablets, and embedded systems. It’s designed for fast, low-power, and reliable data storage with a focus on mobile and embedded applications.
• SD Express: An SD card standard by the SD Association, leveraging PCIe and NVMe protocols to deliver SSD-like performance in a removable, compact form factor. It targets devices like cameras, gaming consoles, and IoT systems.