The MIPI Alliance announced the adoption of the MIPI A-PHY v1.0 specification as an IEEE standard. Published as IEEE 2977-2021, IEEE Standard for Adoption of MIPI Alliance Specification for A-PHY Interface (A-PHY) Version 1.0, A-PHY is the first asymmetric, industry-standard, long-reach, serializer-deserializer (SerDes) physical layer interface for automotive applications.
The process was initiated in October 2020 with the signing of an IEEE-MIPI memorandum of understanding to facilitate A-PHY adoption within IEEE, the world’s largest technical professional organization dedicated to advancing technology for humanity. The project’s IEEE working group was led by Rick Wietfeldt of Qualcomm Technologies Inc. as chair and Tzahi Madgar of Valens Semiconductor as vice-chair.
Developments in advanced driver assistance systems (ADAS), autonomous driving systems (ADS), and in-vehicle infotainment (IVI) have driven a significant increase in the number of cameras, sensors, displays, and computing systems in vehicles. Automotive designs traditionally have relied on SerDes “bridges” to connect these devices and applications to proprietary PHYs, resulting in market fragmentation and, in turn, limited economies of scale.
With A-PHY v1.0, released to MIPI members in September 2020, automotive original equipment manufacturers (OEMs) and suppliers can reduce requirements for these bridges, simplify their designs and cut costs, complexity, weight, and power consumption. With a reach of up to 15 meters, MIPI A-PHY (and now also IEEE 2977) provides an asymmetric data link in point-to-point or daisy-chain topologies, with high-speed unidirectional data, embedded bidirectional control data, ultra-high noise immunity, and optional power delivery over a single cable. It also offers an ultra-low packet error rate of 10‑19 for unprecedented performance over the vehicle lifetime, ultra-high immunity to electromagnetic interference (EMI) effects in demanding automotive conditions, and data rate as high as 16 Gbps, with a roadmap to 48 Gbps and beyond. A-PHY also serves as the foundation of the MIPI Automotive SerDes Solutions (MASS) framework, which simplifies the integration of cameras, sensors, and displays across a vehicle while adding functional safety and security.
The adoption of A-PHY by IEEE marks the latest milestone in the close relationship between the two organizations. MIPI is a corporate member of IEEE and has been a member alliance program of IEEE’s Industry Standards and Technology Organization (ISTO) since MIPI was formed in 2003. The A-PHY adoption is the first time an IEEE-ISTO program specification has become an IEEE standard.
Ongoing development of A-PHY will take place within the Alliance. MIPI A-PHY v1.1, scheduled for release by year-end, will double the downlink data rate (to 32Gbps), double the uplink data rate, and introduce options for implementing A-PHY’s lower speed gears over lower-cost legacy cables. Plans call for it to be put forward for IEEE adoption as well.
MIPI A-PHY v1.0 or IEEE 2977-2021 is accessible to MIPI members via the MIPI website, or by visiting the IEEE SA website. Additional resources, including FAQs, on-demand webinars, and presentations are available on MIPI’s A-PHY webpage, and an automotive workshop is also planned for late 2021.