What Will Be the In-Vehicle Connectivity Gold Standard for ADAS?

The automotive market is very close to adopting the MIPI A-PHY standard for CSI-2 and the DSI-2 standard for connectivity.

Daniel Shwartzberg, director of automotive system solutions at Valens hopes that is will become the connectivity solution of choice. He believes it will offer the automotive industry a standardized SerDes solution for high bandwidth, ultra-low latency, including EMI-EMC robust data links for video.

He explains: “Until this point OEMs and automotive suppliers (Tier 1s) have had to use proprietary, single source solutions for extending video within the vehicle but the A-PHY standard will enable an ecosystem of vendors supplying multiple interoperable products into the market.”

The trouble is, according to Shwartzberg, the words ‘proprietary’ and ‘single source’ aren’t words that the automotive industry enjoys. However, he suggests that a standard offers choice. Yet, there could be a counter-argument that it can restrict innovation. Putting that aside, he describes A-PHY as “a standardized solution offering multi-gigabit link speeds for sensor and display connectivity – things like cameras, radars and LiDARS”.

A-PHY endorsements

Companies and organizations are endorsing A-PHY. They include automotive suppliers such as Aptiv and Denso; camera and sensor vendors such as Omnivision; Leopard Imaging and Sunny Optical, SoC (System on a Chip) vendors like Mobileye; System in Package (SiP) vendors such as LG-Innotek; connector vendors such as Sumitomo; and test equipment vendors like Keysight.

He adds: “The MIPI Alliance A-PHY working group is already working on A-PHY 2.0 and we look forward to seeing the fruits of that activity once it is released. So good is A-PHY that only a few weeks after the launch of A-PHY 1.0, the IEEE adopted it as a standard of their own under their industry affiliate program. This adoption has now been completed, and A-PHY is not just a MIPI specification but an IEEE specification (IEEE 2977-2021). This adoption is significant both in terms of the IEEE endorsing A-PHY as a technology solution but it also means that A-PHY is now accessible not only to the 400 members of the MIPI Alliance but also to the hundreds of companies in the IEEE. I would expect the IEEE to endorse future versions of A-PHY as well.”

Gold standard for ADAS

Shwartzberg also considers A-PHY as the gold standard for ADAS and for full autonomy. At the moment there is A-PHY 1.1, which he says doubles the uplink and downlink speed, offering up to 32Gb/s downlinks and a 200Mb/s uplink. He then comments that A-PHY offers unprecedented bandwidth, long cable length of up to 15 meters and the lowest-in-industry Packet Error Rate (PER) of 10-19 – which, he claims, “is several orders of magnitude lower than competing solutions.”

A-PHY standard benefits

Shwartzberg says the benefits of A-PHY as a standard include the rapid emergence of an ecosystem of suppliers since the A-PHY 1.0 was first released. It has also continued to grow, and by creating a standard it becomes possible to integrate A-PHY technology into the camera and image sensors. “The benefit this brings is less silicon within the camera module, leading to a smaller design, fewer components, lower cost, and less heat dissipation in a zero-airflow environment,” he explains.

“In addition, standardization brings supply chain security with the advantage of receiving A-PHY solutions from multiple vendors. We only have to look at the serious supply chain issues that have afflicted the automotive industry in the last two years – particularly with semiconductors – to appreciate how a standard solution is important to the industry.”

Overall, he suggests that the benefits of A-PHY as a technology are plentiful: it offers more bandwidth than before, extending all the way up to 16Gb/s on a single cable, and cable lengths can go further than before to permit automakers to have more flexible electrical and electronic architectures than was previously possible. A-PHY is also designed to meet, according to Shwartzberg, the “stringent electromagnetic interference (EMI) standards and electromagnetic compatibility (EMC) requirements of the industry by achieving an error rate of 10-19.”

He believes that A-PHY is the ultimate hardware foundation for the software-defined vehicles of the future and says they will leave the factory complete with all the necessary hardware they need to permit functionality to be added on top of the platform over-the-air (OTA). This can include solutions for advanced driver assistance systems (ADAS), whose role is to prevent deaths and injuries by reducing the number of car accidents on the highways.

A-PHY compliant chips

A-PHY compliant chips are already available on the market and they have been since December 2021 with Valens sampling its first generation of A-PHY chipsets, which are allegedly the very first A-PHY chipsets on the market. He explains: “This chipset family is the VA7000 chipset, and it offers link speeds of up to 8Gb/s on a single coaxal cable or shielded pair cable, or up to 4Gb/s on a single unshielded pair, bringing considerable savings to the OEMs.”

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