NXP Unwraps One-chip Automotive Radar SoC Based on 28 nm RF CMOS

This year’s CES event wrapped up yesterday, but here’s another piece of major news from the show. NXP Semiconductor has introduced the SAF85xx, an SoC that the company is calling the industry’s first 28 nm RF CMOS device for safety critical ADAS applications such as automated emergency braking and blind-spot detection.

In this article, we examine the details of this new single-chip radar, we explain how its performance translates to increased automobile safety, and we share commentary from our interview with Matthias Feulner, Senior Director ADAS at NXP Semiconductors.

 

High Performance with 28 nm RF CMOS

Feulner says that a high level of integration is vital in today's and tomorrow’s car designs because of the increasing number of sensors. “The single chip allows us to implement a more compact sensor that’s 30% smaller than previous generations,” he says. “And now that we have many more sensors equipped per vehicle, it's important that we can fit these into locations where there is not a lot of space.” The SAF85xx offers a tiny footprint of 10.6 mm × 11.3 mm.

 

Enabling greater than 300 meter range, the SAF85xx offers twice the performance of NXP’s previous generation RF CMOS radar device. (Click image to enlarge)

 

Also important, according to Feulner, is the performance increase enabled by the 28 nm RF CMOS technology. “The 28 nm RF CMOS allows us to achieve another performance step up—two times the performance of our second generation on the mmWave side, as well as a 40% performance increase on the compute side.”

That’s better performance than NXP’s previous generation of automotive radar chip, which has separate chips for the mmWave front end and the radar controller. While some high-end cars are going toward centralized radar processing today, the majority of vehicle designs will be using edge-based architecture for now. And Feulner emphasized that the SAF85xx is aimed at both.

 

“We are basically integrating this into a scalable platform, along with our advanced radar software, that will allow us to support today's and tomorrow's OEM architectures.”

 

Leveraging Radar Performance of 4D Sensing

The practical impact of the increased performance of the new radar chip is achieving true 360 degree sensing with multiple sensors mounted around the vehicle, according to Feulner. This means being able to do reliable long range detection of objects. But it also means being able to distinguish small objects that are next to larger ones.

 

With the SAF85xx, sensor suites can evolve from weak target identification to a complete 360-degree radar cocoon of safety.

 

As an example, Feulner describes the situation of a fast-moving motorcycle next to cars or trucks on a busy freeway. “Weak target identification separation is a problem, in particular when it comes to vulnerable road users like a motorcycle next to a truck at distances of 140 or 200 meters,” he says.

With the SAF85xx, Feulner says OEMs can do advanced 4D sensing where the radar can sense the vertical dimension of the objects. “It can determine if the object is a bush, or a pedestrian, or if it's something else altogether,” he says. 

Using NXP’s new SAF85xx radar family, engineers can, in combination with other NXP products, build sensor solutions that can surround vehicles in a 360-degree safety cocoon, according to Feulner.

 

For Both Mainstream and High-end Cars

A lot of the demand for more sophisticated sensing in automobiles is due to increased mandates and regulations. “Most vehicles today are equipped with two rear corner sensors for the blind spot detection and one front sensor for the automated emergency braking and cruise control,” says Feulner.

“Now, as 2025 designs are being considered, we've talked to most OEMs in the past half year, and we see that many more sensors are going to be integrated,” he says. In some cases this means designing for full 360-degree sensor suites now and selling upgrades and subscriptions later.

“We think in 2025 most mid range vehicles will be equipped with five radar sensors and premium vehicles will be equipped with ten or more radar sensors (see image below),” says Feulner. On the sensing side, that means rear sensing for collision avoidance and lane change assist.

 

Mid-range cars (left) will need five radar sensors, while premium autos (right) will embed ten or more radar sensors. (Click image to enlarge)

 

Meanwhile, Feulner says he sees requirements for increasing car radar range. Front sensors today are at 200 meters, but going to 300 meters and further. But it is not only the front sensors moving to longer range. “The corner sensors today require typically 70 meters of reach,” he says. “They're going to 140 or 200 meters because there is additional functionality like lane change assist or junction assist, which the corner sensors need to assume.”

Finally, there’s also the trend towards higher resolution. “Road user detection starts with the front sensor, but continues with the corner radar sensors,” Feulner says “That’s because, in these dense urban environments, we want to see all around the vehicle better and whether there are small objects next to larger ones.” High resolution radar sensing is key to these capabilities.

 

NXP’s 3rd Gen of RF CMOS Radar Devices

NXP says that its earlier generation RF CMOS based radar chips were first to ramp to high volume series production for automotive radar, and have already shipped tens of millions of units.

The third-gen SAF85xx is a highly integrated 77 GHz radar smart transceiver SoC that contains four high-performance transmitters, four receivers, a multi-core radar processor with hardware accelerator, Gigabit Ethernet communication interface and memory.

The SoC targets Automotive Safety Integrity Level B (ASIL B) requirements, according to the ISO 26262 functional safety standard and the automotive cybersecurity standard ISO/SAE 21434. More information is available in the SAF85xx fact sheet. NXP says the SAF85xx one-chip family is sampling now to alpha customers.

 

All images used courtesy of NXP Semiconductors