Functional safety

Yes, the functional safety FIT rate is different than the technology FIT rate. Our online mean time between failure (MTBF)/FIT estimator for technology FIT rate is derived using the JESD85 methodology from internal high-temperature operating life (HTOL) and early life failure rate (ELFR) reliability testing. The MTBF and FIT are estimated with a 60% confidence level for reliability.

This method provides an accurate FIT rate for the process technology but does not take into account transistor or gate count, die size or other important factors. We provide functional safety FIT rate based on one of two standards, IEC TR 62380 or SN 29500, which offer a 99% confidence level. Functional safety standards, such as IEC 61508 and ISO 26262, often suggest 99% confidence levels be used for safety-related random failure FIT rate estimation.

For more on functional safety FIT rate, read this Understanding Functional Safety FIT Base Failure Rate Estimates per IEC 62380 and SN 29500. 

IEC 60730 – Applies to automatic electrical controls for use in, on or in association with equipment for household and similar use. This standard also applies to automatic electrical controls for equipment that may be used by the public, such as equipment intended to be used in shops, offices, hospitals, farms and commercial and industrial applications.

IEC 61508 – Covers functional safety aspects to be considered when electrical, electronic and programmable electronic (E/E/PE) systems are used to carry out safety functions.  This standard can be applied to a large range of industrial applications and also provides a basis for many other standards.

ISO 26262 – Applies to functional safety-related systems that includes electrical and/or electronic (E/E) systems and that are installed in series production automotive vehicles.

Both reports are the results of failure mode analysis. The report content and format are different.

A failure modes and effects analysis (FMEA) report follows a process and format that is required by the IATF 16949 standard for automotive product development using the AIAG FMEA requirements standard.  When a failure mode analysis report does not follow the AIAG FMEA process and format it is called a pin FMA.

Providing a pin FMA is required when you have dedicated single function pins that can be easily mapped to a specific failure mode. In contrast, for a microcontroller or processor device the IO’s are typically multi-function and have several layers of in-built pin muxing, meaning that there is no single function and no practical means of mapping a single IO to a single specific failure mode.

In this scenario each pin is assumed to have the same potential for failure and therefore an equal failure rate. Within our FMEDA the package failure rate is calculated as per the IEC 62380 model and then equally divided by the number of pins to provide a FIT per pin failure rate. The FMEDA allows the customer full control over the package failure rate through the applied diagnostic measures down to the individual pin level. Finally, failure modes of IP that include failures of the pins are covered in the analysis of individual IP and a further pin FMA would be redundant.

Please contact your local sales representative.

While we are no longer using the brand SafeTI, these products are still supported and available! If you were using or considering a SafeTI-26262 or SafeTI-61508 product, you will find them under the Functional Safety-Compliant category. If you were using or considering a SafeTI-60730 or SafeTI-QM product, you will now find them listed as Functional Safety Quality-Managed products.