Design for Reliability: Midas Safety Platform

In today’s safety-critical applications—automotive, aerospace, industrial automation—reliability modeling is not just a best practice, it’s a necessity.

One of the most known methodologies for predicting failure rates in integrated circuits is the IEC TR62380 Reliability Model.

The following can provide an estimation for functional safety analysis:

• IEC technical report (TR) 62380 and IEC 61709
• SN 29500, the Siemens AG norm for the reliability prediction of electronic and electromechanical components

What Is IEC TR62380?

IEC TR62380 is a reliability prediction standard that models Failure In Time (FIT) rates based on:

• Die-related failure rate
• Package-related failure rate
• EOS failure rate

The model uses a comprehensive equation to calculate total FIT, incorporating parameters like temperature deltas, duty cycles, and stress factors. For example:

Total FIT={(λ₁​⋅N⋅e^−0.35.α+λ₂​)⋅∑(π_t)_i​​⋅T_i/(T_on​+T_off​)}​+{2.75×10⁻³⋅π_α​⋅∑(π_n​)_i​⋅(ΔT_i​)^0.68⋅λ_3​}+{π₁​⋅λ_EOS​}

This model enables engineers to quantify reliability risks and design mitigation strategies early in the development cycle.

The die failure rate, denoted as λ_die, accounts for failures originating from the semiconductor die itself. The equation {(λ₁​⋅N⋅e^−0.35⋅α+λ₂​) includes technology and transistor information, temperatures and durations for on and off mission profiles, where N is the number of transistors by type, and the exponential term e^(−0.35 × α) models failure probability based on the year of manufacture.

∑(π_t)_i​​⋅T_i/(T_on​+T_off​)} accounts for temperature-related multipliers and durations, normalized by the total on and off time.

This detailed breakdown allows for a nuanced understanding of how operational stress and thermal conditions influence die reliability, making it essential for designing robust semiconductor devices.

The package failure rate, represented as λ_package, evaluates the reliability of the physical packaging of electronic components. 

The equation {2.75×10⁻³⋅π_α​⋅∑(π_n​)_i​⋅(ΔT_i​)^0.68⋅λ_3​}, where π_α is the difference in thermal expansion coefficients of the IC vs. the PCB and λ₃ is the package scale factor by package type and size.

This formulation highlights the importance of thermal cycling and environmental stress in determining package reliability. By quantifying these effects, engineers can optimize packaging materials and designs to minimize failure rates, ensuring long-term durability and performance of electronic assemblies.

Electrical Overstress (EOS) occurs when the voltage or current applied to an integrated circuit exceeds its maximum rated limits. The overstress failure rate, denoted as λ_overstress, captures failures caused by electrical overstress (EOS) events. This can result in immediate damage or gradual degradation of the device. EOS is a common issue in industrial systems where power surges or transient events are prevalent. In the IEC TR62380 model, EOS is captured by the term π₁ × λ_EOS, which accounts for the probability and severity of electrical overstress events. Understanding and mitigating EOS is crucial for enhancing the reliability of ICs in high-power or unstable electrical environments. This simplified yet critical equation allows engineers to assess the risk of EOS-related failures and implement protective measures such as shielding, filtering, and robust circuit design.

The IEC TR62380 reliability model is applied across various industries to ensure the robustness of integrated circuits. In automotive applications, it helps predict the reliability of electronic control units (ECUs) exposed to harsh thermal and mechanical conditions. Aerospace systems use the model to validate the reliability of control electronics in high-altitude and vibration-prone environments. Industrial automation relies on the model to assess the durability of ICs in continuous operation settings. Consumer electronics manufacturers use it to estimate product lifespans and reduce warranty costs. These diverse applications highlight the model’s versatility and importance in modern electronic design.

To streamline the implementation of safety standards like IEC TR62380 and ISO 26262, Cadence offers the Midas Safety Platform.

Key Features

• FMEDA-driven safety analysis for analog and digital flows
• Early phase exploration of functional safety architectures
• Integrated with Cadence tools like Innovus
• Modular architecture for embedded or standalone usage

Midas helps teams automate fault injection, optimize safety mechanisms, and accelerate certification for standards like ISO 26262 and IEC 61508.

Why It Matters

Combining IEC TR62380 modeling with Cadence’s Midas Safety Platform empowers engineers to:

• Predict and mitigate failures early
• Achieve faster safety certification
• Improve design confidence and product reliability

Whether you're designing for autonomous vehicles or industrial robotics, integrating reliability modeling and safety verification is essential for success.

NOTE: IEC 62380 has been replaced by IEC 61709 that adopts and update the Siemens SN29500 norm. From the analytical point of view IEC 61709 has reference failure rates and a given number of derating dependence factors. The recently published IEC TR 63162 defines the reference failure rates to be used for IEC 61709, so that the new standard can be finally used, but being the IEC 62380 model integrated into ISO 26262 part-11, and considering a legacy adoption over many years, it is still de-facto widely used worldwide by the functional safety community.

Learn more about Cadence's Midas Safety Platform.