Successful automotive electronic design requires a focus on safety, performance and customer satisfaction. This makes IC reliability not just a “nice to have” feature, but a fundamental requirement. From advanced driver-assistance systems (ADAS) to infotainment and powertrain controls, every IC must work with exceptional reliability, even in tough conditions. Imagine a tiny circuit flaw in an otherwise not so critical circuit, impacting the reliable operation of a functional safety design element. Like a snowball effect, it can cascade into many problems across complex systems. These range from small inconvenient glitches to catastrophic safety hazards.

Automotive electronics, whether for functional safety or customer satisfaction, must withstand constant vibration, extreme temperatures, dirt, dust and all weather. They need to stay reliable during long operations and frequent start-stop cycles. Because market success and brand reputation depend on these factors, circuit reliability checks need extreme detail and rigor.

Traditional methods for verifying an IC’s physical and electrical correctness include design rule checking (DRC), layout vs. schematic (LVS) and electrical rule checking (ERC). Each focuses on specific design aspects. However, wear-out reliability in automotive applications means analyzing many failure types. These combine physical and electrical limits, like metal spacing rules that depend on the voltages on those metal lines to avoid oxide breakdown, resulting in time dependent dielectric breakdown (TDDB) failures.

Traditional methods often miss subtle, design-specific reliability issues. These often appear under specific operating conditions or complex interactions between circuit blocks and are often missed while running standard verification and simulation flows. This is where advanced EDA tools, like Siemens’ Insight Analyzer, become essential. They enable a crucial “shift-left” in verification, catching problems early, well before physical layout.

The challenge: Uncovering hidden reliability issues

Modern ICs, especially for automotive and other critical applications, are far more complex now. Designs use multiple power domains, advanced power management and complex analog and mixed-signal blocks. All are packed into smaller spaces. This complexity creates the potential for many subtle reliability issues that are very hard to find with traditional methods.

A tiny circuit change can cause a cascading effect. These are not always obvious, static errors. Instead, they often involve dynamic conditions that cause issues like:

• Conditional floating nodes: A node meant to be at a specific voltage becomes disconnected and floats under certain conditions. This leads to unpredictable behavior or leakage.
• Leakage through parasitic body diodes in MOSFETs: Unintended current paths can form through transistor body diodes, especially in multi-power domain designs with switching power rails. This can cause unexpected power use or errors.
• Subtle analog and digital gate leakage: Besides parasitic diodes, gates themselves can leak due to specific voltage conditions or manufacturing variations. This affects power efficiency and long-term reliability.

These issues are problematic because they may not show up during typical functional simulations, which often use limited test vectors. The conditions needed to find these failures might be obscure. They may involve specific power-up/power-down sequences, control signal timings or interactions between blocks in various modes. Relying only on simulation to catch these problems is like finding a needle in a haystack. It’s time-consuming, uses many resources and is often incomplete. Missing these issues has severe consequences: costly silicon re-spins late in design, project delays and compromised product reliability in the field. This is unacceptable for automotive use.

A shift-left approach to reliability

To solve these big challenges, Siemens has been directing circuit designers towards Insight Analyzer. This analysis tool redefines circuit verification. Calibre PERC leads in foundry-driven reliability signoff, especially for physical layout issues like electrostatic discharge (ESD) and known circuit structures. Insight Analyzer complements this by focusing on design-driven reliability verification. It helps circuit designers “shift left” their verification. They can find and fix potential circuit reliability failures much earlier in the design cycle.

Insight Analyzer offers full-chip, transistor-level reliability analysis using proven, unique technology. Its main strength is analyzing transistor configurations within a circuit. It pinpoints problematic setups before extensive simulation or physical layout. This is vital because designers can make changes as they create designs, instead of reacting to problems found much later.

The tool focuses first on tricky leakage sources that other methods don’t easily find. This includes:

• Analog gate leakage: Leakage paths within analog blocks.
• Digital gate leakage: Unintended current flow in digital logic.
• Parasitic leakage: Current paths through unintended parasitic elements, such as body diodes.

Focusing on these three areas helps designers ensure their next-generation designs are reliable. This is especially true for designs with multiple power domains and strict low-power needs. Insight Analyzer uniquely verifies designs without relying on simulation. This greatly reduces verification time and improves coverage.

Designer workflow: Intercepting design creation for early reliability

Circuit designers run Insight Analyzer themselves, typically early in the design process, during design creation, well before layout. The common workflow involves launching Insight Analyzer directly from the transistor design development environment.

Traditionally, designers place transistors and then immediately simulate them. However, many simulations may not truly verify transistor configurations. Instead, they might try to catch basic errors that should have been prevented earlier or confirm functional objectives of the circuit. Insight Analyzer steps in during design creation, letting designers:

1. Load transistor-level netlist: Designers load their transistor-level netlist into the tool.
2. Define project parameters: Simple project settings are made. These specify power rails, isolation controls and how different circuit parts interact, including power states. This helps the tool understand system-level interactions.
3. Select check types: Designers choose the reliability checks they want, mainly focusing on leakage.
4. Run checks: Click the button to launch Insight Analyzer’s analysis.
5. Review results: The tool shows results for the circuit’s overall reliability and provides results visualization and can draw a schematic of the result for further inspection. Figure 1 shows the visualization of results.

Fig. 1: Visualization of results from Insight Analyzer.

This GUI makes it easy for designers to set up and run checks. The benefit is huge: after running Insight Analyzer, reviewing results and fixing errors, designers can then run their simulations with much more confidence. Simulation can then focus on verifying circuit functionality, not debugging basic configuration errors. This saves significant simulation time and makes simulations more effective.

Insight Analyzer also offers flexibility for broader design flows. Once an IP block’s setup is ready, it can easily move from the interactive designer environment to batch mode. This lets CAD teams add these checks to regression flows. It ensures that when IP blocks are used in later designs, their reliability is continuously checked in context, preventing misuse and bad configurations from spreading.

Key differentiating features for robust verification

Several key features make Insight Analyzer stand out. It is a highly productive tool for circuit designers facing complex reliability challenges:

State-based analysis: Unlike static checks, Insight Analyzer uses a state-based approach. This accurately models and analyzes the circuit under various conditions, including power states, functional modes and isolation controls. It finds specific condition combinations that cause reliability violations, often missed by static analysis or incomplete simulation.

Automatic circuit recognition: Before running checks, the tool automatically recognizes circuit elements. It identifies key structural parts in the netlist, similar to how a human designer would. This includes level shifters, logic gates, analog structures and other functional blocks. This intelligence helps the tool “understand” the circuit context. It ensures checks are applied correctly and the tool’s interpretation matches the designer’s intent. This is especially useful for validating new level shifters or isolation controls.

Intuitive results visualization: When a violation is found, Insight Analyzer shows a clear, actionable schematic. This “instant picture” highlights the exact problem location, showing only relevant circuit parts and control signals causing the issue. Annotations show logic highs and lows, guiding the designer to understand the root cause. This helps them make informed decisions about changes. This clarity greatly speeds up debugging.

Advanced deductive reasoning: Insight Analyzer uses advanced deductive reasoning, going beyond static ERC or simulation tools. It can predict complex problems from subtle circuit changes or intricate control logic. For example, a small change in control signal connections can turn a safe circuit into one with contention or floating inputs. Simulation often struggles to provide the right inputs to clearly show these issues. Insight Analyzer understands control logic and signal propagation. This helps it identify unsafe logic levels or control signals, like floating inputs on gates, ensuring circuit robustness (figure 2).

Fig. 2: Insight Analyzer can identify complex problems like contention.

Real-world impact: Success stories in mission-critical design

Insight Analyzer’s state-based checking technology provides real value to users, especially for mission-critical designs.

One user found ten real circuit problems during a tape-out by simply running Insight Analyzer’s basic power contention check. These were simple voltage and connectivity issues missed by earlier checks. This shows the tool’s ability to catch even basic errors that can cause major problems later. The design had successfully passed functional validation with SPICE. This is even before considering more complex state-based analysis for conditional floats. Finding such problems is hard with current simulation methods and test vectors. This highlights Insight Analyzer’s critical role.

Another success story involved a user designing a wireless System-on-Chip (SoC). They found a serious leakage problem using Insight Analyzer’s parasitic checks at the full-chip SoC level. Here, the main power supply was off, but a backup supply stayed active. Leakage current unexpectedly went from the backup supply through several stages. These included a power switch and then body diodes to pass gates. This cascade effect powered parts of the circuit that should have been off. It led to high power consumption and potential functional issues. Such problems are critical in low-power and battery-backed devices, where every microampere of leakage counts. Insight Analyzer made this complex, multi-point failure visible. This allowed for timely correction before tape-out.

These examples show that damaging problems often come from obscure combinations of factors. These include specific states, timings or interactions missed during simulation or in functional models. Insight Analyzer systematically explores these conditions and provides clear diagnostics. This is invaluable for ensuring IC reliability in automotive and other critical applications.

A compelling technology for end-to-end reliability

Insight Analyzer is a big step forward in IC reliability verification. It powerfully complements the existing Calibre PERC reliability verification suite. Calibre PERC excels at foundry signoff checks for physical layout and known circuit structures. Insight Analyzer gives designers a “shift-left” approach to handle design-driven reliability issues at the transistor level.

With its proven state-based analysis, automatic circuit recognition and easy-to-understand results, analog and circuit designers can find and fix potential circuit problems before running long, and often incomplete simulations. Focusing on analog, digital and parasitic leakage helps designers trust their designs. It improves verification coverage, reduces the need for extensive simulation and ensures simulation test vectors focus on true functionality, not basic reliability debugging. With the right tools, designers can create higher quality, more reliable products with short time to market and achieve greater product success.