How IC25.1 Enhances Functional Safety Analysis for Analog Fault Simulation

13 Jul 2025 • 6 minute read

In the high-stakes world of automotive electronics, milliseconds matter. Imagine you're cruising down the freeway in a modern electric vehicle. Suddenly, a sensor glitch causes the braking system to misread the distance to the car ahead. In that split second, the vehicle must decide: is this a real fault occurring in the system or a false alarm? Should it apply the brakes or ignore the signal?

In safety-critical systems like these, there is no room for guesswork. The vehicle's electronics must detect when the system is under fault, classify the faults, and respond appropriately to the conditions—all in real time. This is where Functional Safety analysis (FuSa) becomes not just a design requirement, but a life-saving necessity.

As automotive systems grow increasingly complex—with advancements in autonomous driving, electrification, and real-time smart diagnostics—engineers face the challenge of ensuring that every potential fault occurring in the system is accounted for and addressed appropriately.

That’s where Cadence’s analog fault simulation with Legato Reliability Solution and the new FuSa Results View in Virtuoso Studio IC25.1 comes in, where a game-changing platform brings smarter, faster, and more accurate fault simulation and functional safety analysis to analog and mixed-signal (AMS) design.

With smarter fault tagging, visual systematic diagnostics, and automated safety metrics, IC25.1 empowers engineers to simulate, detect, and analyze faults with greater clarity and confidence, right from the schematic to the safety report.

What’s New in Functional Safety with IC25.1

Cadence’s latest release brings a suite of enhancements that make fault simulation smarter and faster and make ISO 26262 compliance easier than ever before:

Tagging Output Fault Expressions

Label outputs as “Functional” or “Checker” to enable precise classification and better diagnostic coverage.

FuSa Results View with Fault Detection Matrix (FDM)

The FDM color-coded matrix classifies faults into:

DD (Dangerous Detected)
DU (Dangerous Undetected)
UD (Unobserved Detected)
UU (Unobserved Undetected)

Fault Sampling for Large Designs

Simulate a subset of faults and extrapolate coverage—ideal for large, complex designs.

Auto-Stop Criteria

Simulations can now automatically stop once a safety metric threshold is met, saving time and computing resources.

Safety Calculation Form

Safety calculations at a glance, with possible intervention of expert judgment to compute accurate diagnostic coverage metrics.

Seamless Midas Safety Platform Integration

Back-annotate safety metrics into the Midas Safety Platform FMEDA tool, ensuring traceability and ASIL rating compliance.

Training Bytes Video Series: Learn by Watching

We created a Training Bytes video series to clearly explain each enhancement with demos and expert insights.

Video 1: Fault Simulation Capabilities and Limitations in ADE Assembler

Before exploring the new features, it's important to reflect on our starting point. This video discusses the capabilities and limitations of fault simulation in IC23.1 using ADE Assembler, including the setup of fault expressions, result interpretation, and challenges in classifying faults and managing large simulations.

Video 2: What’s New in Functional Safety (FuSa) Enhancements
This video highlights the key improvements in IC25.1, including tagging fault expressions as “Functional” or “Checker” and the new color-coded FuSa Results View, designed for smarter and faster fault simulation.

Video 3: Tagging Output Fault Expressions and Running Functional Safety Checks in ADE Artist
This demo shows you how to apply the new tagging feature in ADE Artist. You’ll learn how to distinguish between functional and checker outputs, which is essential for accurate fault classification and functional safety analysis.

Video 4: Need for Fault Sampling Options and Auto Stop Criteria in FuSa Analysis
Simulating every fault in a large design isn’t always practical. This video explains the motivation behind introducing fault sampling and auto-stop criteria—two features that help you simulate smarter, not harder.

Video 5: Performing Functional Safety Checks in ADE Artist with Fault Sampling Options and Auto Stop Criteria
Now that you understand the theory, this demo shows you how to configure and run simulations using sampling and auto-stop. You’ll see how to reduce simulation time while maintaining diagnostic accuracy.

Video 6: Generating and Interpreting the Functional Safety (FuSa) Report from ADE Artist
Finally, this demo walks you through the new FuSa report. You’ll learn how to interpret the Fault Detection Matrix, use expert judgment to reclassify faults, and generate a report that supports ISO 26262 compliance.

Together, these videos form a complete learning path—from understanding the limitations of the past to mastering the powerful new features of IC25.1. Whether you’re just getting started or looking to refine your FuSa workflow, this series is your go-to resource.

Try It Yourself: Hands-On with the Rapid Adoption Kit (RAK)

Want to explore these features in a real design flow, by diving into Functional Safety (FuSa) or refining your workflow? Use the Fault Simulation in Virtuoso ADE Assembler and Virtuoso ADE Artist Rapid Adoption Kit (RAK) to walk through fault simulation, tagging, sampling, auto-stop, and FuSa reporting in Virtuoso ADE Assembler and ADE Artist. This RAK includes step-by-step instructions, example schematics, and simulation setups to help you try out everything you’ve seen in the videos—hands-on and at your own pace.

Take your FuSa skills to the next level with the RAK on Functional Safety Verification: Analog Fault Campaigns with Virtuoso ADE Artist and Midas (FMEDA). This RAK focuses on seamless data exchange between ADE Artist and Midas for detailed safety analysis allowing you to Run analog fault campaigns using Spectre Legato Defect Simulation, aligned with ISO 26262. Extract design hierarchy and set up FMEDA in Midas. Annotate and analyze safety metrics like DC, SPFM, and LFM in the Midas platform.

Conclusion: Designing for Safety

In the race toward smarter, safer, and more autonomous vehicles, it's not just about speed—it's about stopping safely when it matters most. With Cadence Virtuoso IC25.1, you are no longer guessing how the designs will behave under fault conditions—you are simulating it, visualizing it, and optimizing it with operating precision.

Whether you're building the next-gen EV powertrain or a life-saving medical sensor, the enhanced fault simulation and functional safety features in IC25.1 give you the tools to predict the unpredictable. From tagging outputs to auto-stopping simulations, from visualizing fault matrices to integrating with FMEDA platforms to achieve standards—this is not just a software upgrade; it's a first in generation safety revolution.

So, the next time your car brakes just in time, remember: it’s not magic—it’s meticulous engineering, powered by smarter fault simulation.

Don’t miss the Training Bytes series, try the two RAK Fault Simulation in Virtuoso ADE Assembler and Virtuoso ADE Artist, Functional Safety Verification: Analog Fault Campaigns with Virtuoso ADE Artist and Midas (FMEDA) and design for safety.

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