MIPI Alliance Releases A-PHY v1.1, Doubling Maximum Data Rate and Adding New Implementation Options to Automotive SerDes Interface

By Tiera Oliver

Associate Editor

Embedded Computing Design

January 19, 2022


MIPI Alliance Releases A-PHY v1.1, Doubling Maximum Data Rate and Adding New Implementation Options to Automotive SerDes Interface
Image Courtesy of MIPI Alliance

The MIPI Alliance announced the release of MIPI A-PHY v1.1, the next version of the automotive serializer-deserializer (SerDes) physical-layer interface. 

Version 1.1 doubles the maximum available downlink data rate from 16 Gigabits per second (Gbps) to 32 Gbps and includes other enhancements to help automotive OEMs and their suppliers implement high-performance image sensors and displays in next-generation vehicles. 

A-PHY v1.1 doubles the total downlink bandwidth by adding support for Star Quad (STQ) cables that provide dual differential pairs of conductors within a single shielded jacket. This enables two A-PHY ports over a single cable, saving cost, weight, and complexity compared with using two separate coaxial or shielded twisted pair cables. 

Version 1.1 also adds optional PAM4 encoding for A-PHY downlink gears G1 and G2, with data rates of 2 Gbps and 4 Gbps, respectively. PAM4 encoding features lower modulation bandwidth for sub-1 GHz operation, allowing manufacturers to migrate to A-PHY while using either legacy cables on current platforms or lower-cost cables on new platforms. 

The new version also adds a faster uplink gear with an available data rate of up to 200 Mbps, twice the rate of the existing uplink gear, providing more bandwidth for command and control of automotive peripherals. A-PHY v1.1 is fully interoperable with A-PHY v1.0, and devices using both specifications can coexist on the same network.

These enhancements enable automotive manufacturers to design next-generation applications that use the latest camera and display technologies, including higher-performance instrument clusters and infotainment displays, interior driver and passenger monitoring systems, virtual side mirrors and other ADAS, IVI, and ADS applications. 

Now that it has been formally adopted by the MIPI Alliance, v1.1 will be brought forward for adoption as an IEEE standard. In 2021, IEEE adopted A-PHY v1.0 as IEEE 2977-2021.

To learn more about MIPI A-PHY, please join the virtual MIPI A-PHY Automotive Industry Forum, Jan. 26 at 8 a.m. PST, when A-PHY Working Group leaders will provide an overview of the enhancements in v1.1 and then gather feedback on requirements and proposed features for the next version of the specification. Representatives from automotive OEMs and Tier 1 suppliers are particularly encouraged to attend. Register for the forum

The MIPI Alliance also hosted a virtual Automotive Workshop in November to provide more in-depth education on its MASS framework. Recordings of the sessions are available on the MIPI website. In addition, a white paper, “An Introductory Guide to MIPI Automotive SerDes Solutions (MASS),” offers an overview of each layer of the MASS framework. 

For more information, visit: https://www.mipi.org/

Tiera Oliver, Associate Editor for Embedded Computing Design, is responsible for web content edits, product news, and constructing stories. She also assists with newsletter updates as well as contributing and editing content for ECD podcasts and the ECD YouTube channel. Before working at ECD, Tiera graduated from Northern Arizona University where she received her B.S. in journalism and political science and worked as a news reporter for the university’s student led newspaper, The Lumberjack.

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