The latest Universal Flash Storage (UFS) Card Extension Standard boosts performance while reducing power consumption...
Like most new memory or memory interface specifications, the latest iteration of the Universal Flash Storage (UFS) Card Extension Standard unsurprisingly boosts performance while reducing power consumption, but it’s also poised to find itself in use cases that didn’t exist at the initial spec’s inception. And as an interface standard, it could potentially support persistent memory other than flash.
Version 3.0 of the JESD220-2B standard released by JEDEC Solid State Technology Association defines functionality closely aligned with the popular UFS 3.0 embedded device standard already widely recognized in many high-end mobile and consumer-focused applications. Compared to its predecessor, it doubles the maximum interface performance to 1.2 GB/s from a maximum of 600 MB/s.
As an interface designed for use in applications where power consumption needs to be minimized, the UFS card standard is well suited for mobile devices and automotive systems, and increasingly Internet of Things (IoT) applications. All three use cases have an “instant on” expectation from users, which can now be better met with the introduction of boot support — devices can now start up more quickly by using a UFS card.
Version 3.0 has been streamlined, too, to improve interoperability and reduce development complexities eschewing features that are not needed for a removable card, including Product State Awareness (PSA), Replay Protected Memory Block (RPMB), Context, Priority of Logical Unit, and Dynamic Capacity. In addition, storage management is simplified by minimizing the number of logical units.
What remains most important — even though use cases for the UFS card have changed since its introduction — is mobility, as it’s valued by 5G, automotive, IoT, and even artificial intelligence applications at the edge, said HeeChang Cho, co-vice-chair of JEDEC Electrical Specifications and Command Protocols subcommittee. “Providing high performance and high reliability while consuming low power is critically important.” For example, 5G transfer speeds combined with increased content sizes, such as ultra-HD video are driving the need for faster, bigger storage in smartphones.
The limited power budget remains a challenge when updated the UFS card specification, added Desi Rhoden, JEDEC committee chair for Solid State Memories. “Since UFS is primarily intended for mobile applications — and was designed that from the very beginning — it becomes a challenge to double the performance without impacting power.”
In addition, the majority of UFS cases also require a great deal of reliability, which can’t be compromised in favor of other improvements. “It’s becoming increasingly important for applications like the automotive industry,” he said. “The last thing any of us want is to be is in a car that crashes because some technology failed. The long-term reliability in multiple environments becomes extremely critical.”
Embedded UFS is commonly used in most smartphones today, said Cho, but a card provides more flexibility while still delivering high performance and working with the controllers already built into these devices. A bootable card also allows for the creation of devices that may not have their own memory, with everything being contained in the card, adds Rhoden. “There’s a wide array of applications that become possible again that weren’t before.” In addition, the security can be handled right on the card. Even in terms of security, in terms of all kinds of things, because it’s all just contained in the card. “All your memory and everything you need is basically all on the card.”
Another requirement that a lot of UFS card applications have in common today is the need for fast booting — consumers have come to expect it from their phones, and it’s a critical reliability characteristic for the infotainment systems in today’s modern vehicles, said Rhoden. “When you turn the key, you don’t want to have to sit around and wait for something to boot.”
Similarly, IoT devices at the edge can also take advantage of the high reliability of a UFS card. “The booting feature enables the UFS card to be used for both primary storage as well as removable storage,” Cho said. The low power consumption can also be viewed as having more power stability, which contributes to the reliability. Another inherent characteristic of a UFS card is that the host can send commands continuously, even while the UFS card is transferring data for processing previous commands, he added. This means an application can perform I/O operations while other applications simultaneously without impairing performance.
The milestone of hitting its third iteration means the UFS card specification is somewhat mature but still has a lot of runway left, said Rhoden, in part because it’s not a specific memory type, but an interface technology that could be used for any persistent memory. “You could have this same wrap around virtually any kind of memory. What we’ve defined is the interface itself, and the protocol for all of the interfaces. That’s what UFS is.”