The Design Chronicles Blogs

Automotive ICs are expected to last 15 years, yet they are vulnerable to incredible environment- and stress-induced failures. As the industry eventually moves to full automation for vehicles, functional safety will always be a key consideration for the underlying technologies. That’s why it takes a proven functional safety flow to build reliability into these devices.

Reliability is measured by the failure-in-time (FIT) rate, where:

1 FIT = 10^-9 --> 1 failure per billion hours (once in about 114,155 years)

At this year’s Design Automation Conference (DAC) in Austin, Cadence’s booth featured a Digital Experience room where tech experts presented talks on a variety of topics. During one session, Alessandra Nardi, a software engineering group director, discussed Cadence’s automotive design flow. In this post, I’ll focus on safety and reliability.

According to Nardi, automotive semiconductors face stress-induced failure mechanisms including:

• Electromigration
• Aging
• Electrostatic discharge
• Electromagnetic interference
• Latch-up (burnout from thyristors formed from parasitic transistors)
• Electrical over-stress (thermal damage from current or voltage level beyond device specifications)

In addition, they also face environmentally induced failure mechanisms such as:

• Temperature effects
• Soft errors (for example, alpha particles can change memory cell values)

The standard for automotive functional safety is ISO 26262, which defines processes to follow (including one for software tools compliance), hardware/software performance to achieve, and safety documentation to produce. Cadence has been working closely with automotive semiconductor companies for more than a decade. The company’s functional safety flow provides fault detection to measure FIT rate, helps you map failure modes to safety goals, estimates and distributes FIT with fault-tree analysis, provides statistical generation of faults related to safety goals and fault simulation, and addresses safety classification and certification.

Cadence also participates in ISO 26262 compliance, working to make the compliance process faster and less expensive for automotive engineers. Across all business units are employees who have been trained by TÜV SÜD and certified as functional safety engineers. In addition, there are engineers working on Tensilica IP who have received ISO 26262 training.

By meeting functional safety standards, automotive engineers can be confident that their designs will operate as intended even when something unexpected or unforeseen occurs. You can learn more about Cadence’s tools and technologies for automotive design here. For more details on tools for meeting functional safety requirements, check out this white paper.

Christine Young