April 7, 2022
Ludovic Rota understands the importance of ensuring functional safety for mission-critical products. As a function safety expert at onsemi, Rota is tasked daily with not only identifying potential design flaws in the company’s semiconductor solutions, but also mapping them to real-world impacts for the larger product system in which they will be installed.
Rota’s work is especially important to onsemi as it serves unprecedented demand for its more than 80,000 individual semiconductor products. The company’s 2021 revenue of $6.74 billion represented an incredible year-over-year increase of 28.3%, which onsemi attributes to the explosive growth of the electric vehicle, advanced driver assistance system (ADAS), alternative energy, and industrial automation markets.
When they’re incorporated into these and other customer product systems, onsemi solutions must operate flawlessly to deliver high levels of performance, while also protecting human health and safety. Even as onsemi rushes innovative new designs to market to meet skyrocketing demand and support ever-expanding customer applications, it must conduct extremely rigorous safety analysis for every component and product system.
Over a nearly 20-year career — most of it spent at onsemi and its predecessor, ON Semiconductor — Rota has contributed to the onsemi global functional safety team (led by Yves Renard, committee member of the ISO 26262 and the P2851 standards) to define both best practices and an associated suite of advanced technologies in functional safety analysis to meet this complex challenge.
To ensure the highest level of functional safety, Rota emphasizes that it’s essential to replace human judgment with scientific analysis as much as possible. This is important as Rota and his team conduct the safety analysis — including, but not only, failure modes, effects, and diagnostic analysis (FMEDA) — of the components. They then assist the customer in conducting their own system safety analysis by using the component’s safety analysis when the customer integrates it.
“Simulation helps semiconductor engineers study the building blocks of a semiconductor component, such as individual circuits, in a numerical and scientific way,” he explains. “It’s relatively easy to study a specific low-level circuit, which we call a ‘module,’ and say with confidence that it will function electrically as expected — because we’re looking at straightforward, physics-based problems. We can identify faults, such as electrical shorts or open wires, and address those with relative ease.”
The real safety challenge, according to Rota, emerges when all those modules are connected together in a “block.” Blocks provide a higher-degree function by bringing together multiple modules. Any fault in a specific module can trigger a larger failure mode in this more complex system, which could impede onsemi’s ability to comply with functional safety standards such as ISO 26262 and launch its products confidently into the automotive marketplace.
“Traditionally, safety analysts had to apply a lot of expert judgment as they looked at integrated semiconductor blocks,” says Rota. “It was more of an art than a science. It was difficult, if not impossible, to identify a block-level failure and link it directly to a fault in a lower-level component. The cause-and-effect relationship was often not well understood because it was limited by human reasoning and cognition. Analysts had to rely on their own judgment, along with a time-consuming process of trial and error, to ensure that blocks were functioning properly in terms of safety.”
Given onsemi’s commitment to extreme product innovation, accelerated speed to market, and uncompromising product safety, onsemi global functional safety team knew the company required a better, more scientific basis for analysis.
For years, Rota has used Ansys medini to model and analyze integrated semiconductor blocks to ensure their complex architecture will deliver safe, reliable, and predictable performance when installed in a customer’s final product, such as a passenger car. medini enables Rota and his team of analysts to quickly and seamlessly model each block’s many components, connections, and interfaces — and then identify likely failure modes.
When a potential top-level failure is flagged, Rota notes that medini makes it easy and straightforward to directly link that failure to a design fault in a lower-level component.
“Ansys medini allows us to map cause and effect in a scientific way, instead of relying on human judgement or guesses,” says Rota. “It presents us with the information we need to identify the top-level problem and arrive at a resolution. There is a direct linkage between the FMEDA of lower-level modules and the FMEDA of higher-level blocks.”
After years of leveraging the modeling and analysis capabilities of medini, Rota can’t imagine conducting this critical discovery in any other way.
“At onsemi, medini functions as a ‘safety analysis cockpit’ that puts all the required information together and displays it to us in a logical manner,” he states. “We can see all the relationships and dependencies in the block. The design’s complexity is simplified and mapped. The linkages between lower-level faults and higher-level failures are obvious, so we don’t have to guess anymore.”
The extreme pressures faced by semiconductor manufacturers aren’t going away any time soon. For the foreseeable future, onsemi will continue to be challenged to meet dramatic demand growth with a steady stream of innovative semiconductor solutions that deliver increased power, smaller size and other performance features.
As onsemi rushes to market, its engineering team needs to perform thorough and comprehensive functional safety analysis at every stage of product development and system integration, in order to deliver reliable performance in a range of demanding applications. medini helps achieve this careful balance between development speed and analytic rigor, powering the next generation of semiconductor solutions.
Learn more about onsemi’s best practices in functional safety analysis by viewing Ludovic Rota’s presentation at the 2021 Ansys Digital Safety Conference via the on-demand Digital Safety Conference.