Community Translation: AURIX™ MCU: FMEDA – KBA236341
Version: **
Failure Modes, Effects, and Diagnostic Analysis (FMEDA) is a quantitative bottom-up analysis. It is performed only on hardware, as this is an analysis of the effect of random hardware faults on a safety requirement or safety goal, including quantitative estimation of failure rates and the probability or rate of a safety goal violation.
One of the objectives of ISO 26262-5:2018 is to provide evidence (based on the hardware architectural metrics) for the suitability of the hardware architectural design of the item to detect and control safety-related random hardware failures.
ISO 26262-5:2018 describes two hardware architectural metrics: Single Point Fault Metric (SPFM) and Latent Fault Metric (LFM) and associated target values (ASIL dependent) for the evaluation of the effectiveness of the architecture of the item to cope with random hardware failures.
As required by ISO 26262-5:2018, evaluate safety goal violations because of random hardware failures. The objective of this analysis is to provide evidence that the residual risk of a safety goal violation because of the random hardware failures of the item is sufficiently low.
The following are the two alternative methods according to ISO 26262-5:2018:
- Method 1: The Probabilistic Metric for Random Hardware Failures (PMHF) represents a quantitative analysis that evaluates the violation of the considered safety goal by random failures of the hardware elements.
- Method 2: The Evaluation of Each Cause of safety goal violation (EEC).
Infineon uses the PMHF method, which is a quantitative analysis and the result is compared with a target value (ASIL dependent).
Target values for SPFM, LFM, and PMHF out of ISO 26262-5:2018 are:
Table 1 Possible source for derivation of the target single-point fault metric value
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ASIL B
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ASIL C
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ASIL D
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Single-point fault metric
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≥ 90%
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≥ 97%
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≥ 99%
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Table 2 Possible source for derivation of the target latent-point fault metric value
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ASIL B
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ASIL C
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ASIL D
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Latent-point fault metric
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≥ 60%
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≥ 80%
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≥ 90%
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Table 3 Possible source for derivation of the random hardware failure target value
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ASIL B
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ASIL C
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ASIL D
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Random hardware failure target
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< 10-7 h-1 |
< 10-7 h-1 |
< 10-8 h-1 |
The outcome of this safety analysis (FMEDA) is the hardware architectural metrics (SPFM and LFM) and PMHF according to ISO 26262-5:2018.
