As a tech analyst, I follow ON Semiconductor closely. The semiconductor company, known for its niche in power and signal management, discrete, logic and other custom devices, has become a significant player in the growing automotive electrification market over the last several years. As vehicles are getting more intelligent, more efficient, more autonomous and generally more complex, they include an increasingly large and advanced set of circuits and components. Extraordinarily crucial are the sensors that comprise ADAS—the advanced driver assistance systems that help keep our fellow motorists and us safe on the road. These sensors include cameras, RADAR and LiDAR, which gather data, run it through a processor (or set of processors) and use that information to make decisions in real-time about how the vehicle should respond to occurrences inside and outside of the vehicle. ON Semi recently announced a new SiPM array, which we will define shortly, that promises to bring LiDAR capabilities to ON Semi’s automotive sensor product line. Let’s take a look at the news.
To understand the value of ON Semi’s new array, one must first have a basic concept of what LiDAR is and how it is used in the context of automotive safety. Many are familiar with LiDAR’s cousin, RADAR, from the local weather report. While RADAR utilizes radio waves to detect objects, LiDAR leverages laser light rays. RADAR works most effectively when detecting objects at a long distance at a lower resolution. On the other hand, LiDAR can provide highly detailed, 3D maps of close-range surroundings (up to 300 meters), including the exact size of objects and the distance between itself and those objects.
A LiDAR system works by beaming out a short laser pulse. When the light hits an object in its pathway, some of it reflects back to the system, where it is detected by a sensor, such as the ArrayRDM-0112A20-QFN. The sensor records how much time the round trip of the laser pulse takes, using the speed of light to calculate a direct time-of-flight measurement of distance. This is repeated many, many times over at many different locations across the environment.
Since all pixels captured through LiDAR carry depth information, they can provide crucial context and detail to the 2D images of the surroundings captured by other sensors. While LiDAR, as of yet, does not perform well in precipitation or other lousy visibility conditions, it’s got the other ADAS sensors to provide redundancy and pick up the slack when needed.
New SiPM Array
ON Semi refers to its newly announced SiPM (silicon photomultiplier) array, the ArrayRDM-0112A20-QFN, as the first linear array of SiPMs to hit the commercial market and the first automotive-qualified SiPM. So, what’s an SiPM, you might ask? An SiPM is a category of sensors that can be leveraged to capture the light reflected back to a LiDAR system. SiPMs, due to their impressively high 1,000,000x internal gains, can pick up even a single photon of light. With that sensitivity, the sensors can set very low thresholds, in turn, enabling them to pick up even the faintest, single-photon return signal. This single photon-sensitivity, according to ON Semiconductor, paired with time-correlation methods, also allows the sensor to differentiate between the actual return signal and the “noise” of sunlight and other light sources.
This sensitivity makes SiPMs very well-suited to automotive applications of high-performance LiDAR, where accurate 3D point maps make the difference between literal life and death. To that end, ON Semiconductor touts its new SiPM array’s superior detection, low noise and dark count rates, low operational voltage, temperature sensitivity and process uniformity. The ArrayRDM-0112A20-QFN consists of a 12-pixel linear area of SiPMs, capable of achieving 18% photodetection efficiency at 905 nm (which ON Semi says is the standard wavelength for affordable, broad market LiDAR).
With this unique offering, ON Semi seems to have found yet another automotive niche it can cover. As the first SiPM of its kind, it already has a head start on any other rival offerings that may pop up in the coming years. This new array's economy stands to increase the adoption of LiDAR systems worldwide, in turn moving the ball further down the court for the autonomous driving market as a whole. When we eventually get to fully autonomous vehicles, it’s going to be remarkable how much of ON Semi’s technology is inside.
Note: Moor Insights & Strategy writers and editors may have contributed to this article.