Mastering AI Chip Complexity
Explore challenges and solutions in AI chip development
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Definition
UFS, or Universal Flash Storage, is a type of non-volatile memory commonly used in mobile devices like smartphones and tablets, as well as in digital cameras and other electronic devices.
The UFS flash memory specification is supported by consumer electronics companies such as Nokia, Sony Ericsson, Texas Instruments, STMicroelectronics, Samsung, Micron, and SK Hynix. UFS is positioned as a replacement for eMMCs and SD cards. The electrical interface for UFS uses the MIPI Alliance’s M-PHY high-speed serial interface targeting 23.32Gps per lane with 2.9GBs per lane, which is the latest version (UFS4.0, released in August 2022). UFS implements a full-duplex serial LVDS interface that scales better to higher bandwidths than the 8-lane parallel and half-duplex interface of eMMCs. Unlike eMMC, UFS is based on the SCSI architectural model and supports SCSI Tagged Command Queuing. The standard is developed by, and available from, the JEDEC Solid State Technology Association.
UFS also supports features such as multiple queues, command reordering, and power gating, which improve performance and power efficiency. It is currently available in several different versions, such as UFS2.0, UFS2.1, UFS3.0, UFS3.1, and UFS 4.0.
| UFS Version | Release Date | Max Speed per Lane | Max Total Throughput |
| UFS 2.0 | 2013 | ~5.8 Gbps | ~1.2 GB/s |
| UFS 2.1 | 2016 | ~5.8 Gbps | ~1.2 GB/s |
| UFS 3.0 | 2018 | ~11.6 Gbps | ~2.9 GB/s |
| UFS 3.1 | 2020 | ~11.6 Gbps | ~2.9 GB/s |
| UFS 4.0 | 2022 | 23.32 Gbps | 5.8 GB/s per dual lane |
How Does UFS Work?
Universal Flash Storage works by using a combination of hardware and software to store and retrieve data on non-volatile flash memory chips. Here is a brief overview of how UFS works:
UFS uses a layered architecture, consisting of a UFS host/device controller layer, a transport layer (UniPro), and a physical layer (MIPI M-PHY). The host interface layer is the interface between the host (e.g., a smartphone) and the UFS storage device. UFS is also divided by host and device, with the host handling the data transfer from the application processor to the device as storage IC and the device managing the flash memory chips and other hardware components. A command queue system manages data transfers between the host and the device. This approach allows the device to handle multiple read and write requests simultaneously, improving performance.
UFS uses advanced power management techniques to reduce power consumption. For example, the memory type supports a feature called "power gating," which allows unused components to be turned off to save power.
For security reasons, UFS needs to encrypt/decrypt the payload. The UFS device prohibits writing into its locations when configured as write protected but there are no such restrictions for read. To address this concern, the UFS controller encrypts the data during the write and decrypts the data during the read. Several encryption algorithms are supported: AES-XTS, Bit locker-AES-CBC, AES-ECB, and ESSIV-AES-CBC, with different AES key sizes – 128, 192, and 256 bits. The higher the key size, the higher the security level.
Benefits of UFS
Here are several benefits of using UFS (Universal Flash Storage) as a storage solution in electronic devices, such as smartphones, tablets, and other mobile devices:
- Faster Data Transfer Speeds. UFS 4.0 can achieve the highest data transfer rate of around 46 Gbps by utilizing two available lanes of MIPI M-PHY Gear5 transmission lines with MIPI UniPro v2.0.
- Improved Performance. UFS is designed to improve overall device performance by minimizing latency and improving data transfer speeds at 5.8GBs per dual lane on UFS4.0. It also supports advanced features like command queuing and power gating, which can further improve performance and reduce power consumption.
- Better Power Efficiency. UFS supports advanced power management techniques, such as power gating, to minimize power consumption. Utilizing the M-PHY hibernate mode provides the lowest M-PHY power consumption with HS-burst recovery time in microseconds. On the other hand, utilizing the stall power mode allows a much faster recovery time to HS-burst operation but with less power savings. These options provide flexibility for the SoC to utilize the best practices to match the data traffic profile, and can help to extend battery life in mobile devices and reduce power usage in other electronics.
- Higher Storage Capacity. UFS can support higher storage capacities with 1TB than other storage solutions, such as eMMC with 256GB. This means that UFS can provide more storage space for the OS, application software, and data.
- Safety with Security. JEDEC, the standards body for both eMMC and UFS, has introduced support for inline encryption (IE) and Replay Protected Memory Block (RPMB) to protect data confidentiality and prevent eavesdropping and man-in-the-middle attacks native to the UFS specification. Robust encryption mechanisms are proposed to allow for standardization across host and device combinations.
| Benefit | Details |
| Faster Data Transfer | UFS 4.0 supports up to 46 Gbps with dual MIPI M-PHY Gear5 lanes (5.8 GB/s per dual lane) |
| Improved Performance | Lower latency, multiple queues, command reordering, power gating |
| Power Efficiency | Power gating, hibernate mode, stall mode, adaptive power savings |
| Higher Storage Capacity | Up to 1TB; higher than eMMC (256GB max) |
| Enhanced Security | Inline encryption (AES variants), RPMB, and protection against MITM attacks |
UFS Use Cases
Overall, UFS is a versatile technology that can be used in many applications that require high-speed and high-capacity storage, low latency, and low power consumption. Some common use cases for UFS include:
- Smartphones and Tablets. UFS is commonly used for storage in smartphones and high-end tablets due to its high speed and reliability. With UFS, mobile devices can offer faster app loading times, quicker data access, quicker boost, and improved overall performance.
- Digital Cameras and Camcorders. UFS is often used in digital cameras and camcorders to store high-resolution photos and videos. The high write speeds of UFS allow for faster saving of large files, and the high read speeds enable quicker transfer of files to a computer.
- Automotive. UFS is increasingly being used in automotive applications such as infotainment systems, advanced driver assistance systems (ADAS), and navigation systems. UFS enables fast boot times and quick access to data, both essential for real-time applications in the automotive industry. An important feature that makes UFS ideal for automotive applications is its reliability. UFS lowers overall risk of wear and tear of the storage device by allowing the storage device to notify the host about large temperature variations. When the storage device indicates alarming temperatures, the host can throttle down or take actions to cool down the device temperature.
- Virtual Reality (VR) and Augmented Reality (AR). UFS is ideal for VR and AR devices, which require high-speed and low-latency storage for immersive experiences. These devices can quickly load and process large amounts of data at 5.8GBs per dual lane on UFS4.0, resulting in a smoother and more responsive experience.
- Wearable Devices. UFS is also used in wearable devices such as smartwatches and fitness trackers, where space is at a premium and high-speed and low-power storage is essential. Wearable devices can offer longer battery life, particularly using the UFS hibernation mode.
- Hard Disk Drives (HDD). HDD storage architecture combines traditional spinning disks with OptiNAND technology. The drive adds an iNAND UFS embedded flash drive onboard, which alongside proprietary firmware and SoC improvements, is meant to address storage demands of enterprise customers.
| Use Case | Application / Benefit |
| Smartphones / Tablets | Faster app load, better performance, quicker data access |
| Digital Cameras / Camcorders | Fast write speeds for large files, quick transfer to PC |
| Automotive Systems | Fast boot times, real-time data access, temperature alerts for reliability |
| VR/AR Devices | High-speed, low-latency storage for immersive experiences |
| Wearables | Power-efficient, compact storage, long battery life with hibernation mode |
| HDD with OptiNAND | Combines UFS with traditional HDD for enterprise-grade storage efficiency |
UFS and Synopsys
Synopsys offers the industry’s leading silicon-proven UFS Subsystem Design IP and protocol verification solutions. Synopsys IP for UFS Host Controller, UniPro Controller, and M-PHY Gear4 and Gear5 rates support the latest UFS 4.0 specification. These controllers enable high-speed data transfer, low-power consumption, and support for advanced features such as queue management, power management, and virtualization. Synopsys protocol verification solutions including Verification IP, transactors, speed adaptors, and virtual solutions for simulation and emulation developed in collaboration with market makers and used to verify silicon-proven Synopsys IP.
- The Synopsys Universal Flash Storage (UFS) Host Controller IP is a standard-based serial interface engine for implementing the JEDEC UFS interface in compliance with the JEDEC UFS and UFS Host Controller Interface (UFSHCI) standards, as well as the UFS removable card v1.1 and Unified Memory Extension (UME) standards. The Synopsys UFS Host Controller IP is a high-performance, low-power interface that is primarily used in applications where data is stored on embedded or removable non-volatile mass storage memory devices. The UFS Host Controller IP integrates the UFS host controller application layer with a pre-configured Synopsys MIPI® UniPro protocol stack that is optimized for UFS host applications.
- The silicon-proven Synopsys MIPI M-PHY IP, compliant with the latest MIPI M-PHY v5.0 specification, supports speeds up to 23.32 Gbps per lane. The IP is optimized for a broad range of high-speed interfaces for applications including JEDEC Universal Flash Storage (UFS) and UniPro interfaces, which are widely used in mobile and automotive applications.
- Synopsys also provides automotive-grade UFS controller and MIPI M-PHY, which have been qualified by AECQ-100 with –40 °C to 125 °C as grade 1 and achieve the ASIL-B functional safety level.
- Synopsys Verification IP for UFS4 covers the latest protocol specifications: JEDEC UFS 4.0, UFS 2.1, HCI 4.0, UME 1.1, UMEHCI 1.1, MIPI UniPro 2.0, MIPI M-PHY 5.0, and more. Ready-to-use source-code test suites for UFS host and device help achieve protocol compliance and reduce time to verification. In-circuit and virtual solutions over the Synopsys ZeBu® Emulation and Synopsys HAPS® platforms, the industry’s fastest, enable running real-world application payloads for both application-level function and performance verification.
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