{"id":593,"date":"2018-04-17T13:04:16","date_gmt":"2018-04-17T20:04:16","guid":{"rendered":"http:\/\/blogs.mentor.com\/tessent\/?p=593"},"modified":"2026-03-26T16:04:47","modified_gmt":"2026-03-26T20:04:47","slug":"how-to-measure-iso-26262-metrics-of-analog-circuitry","status":"publish","type":"post","link":"https:\/\/blogs.sw.siemens.com\/tessent\/2018\/04\/17\/how-to-measure-iso-26262-metrics-of-analog-circuitry\/","title":{"rendered":"How to measure ISO 26262 metrics of analog circuitry"},"content":{"rendered":"<p>By Stephen Sunter\u00a0 &#8211; Mentor, A Siemens Business<\/p>\n<p><em>ICs designed for safety-related automotive systems are expected to operate safely for the lifetime of the vehicle. The manufacturing test strategy and on-chip runtime test capabilities are important aspects of achieving that zero-DPPM goal.<\/em><\/p>\n<p><!--more--><\/p>\n<p>Much discussion of test and diagnosis for automotive ICs addresses digital logic and memories, but most (70% or more) of the field failures occur in the mixed-signal portion of the chip. These defects, even in small numbers, can\u2019t be tolerated in safety-critical automotive applications. Mentor developed the Tessent DefectSim analog defect simulator to address this growing need for analog test tools. Tessent DefectSim automates the job of measuring a circuit&#8217;s tolerance to defects.<\/p>\n<p>&nbsp;<\/p>\n<p>The ISO 26262 standard provides for defect tolerance. Since the focus of the standard is minimizing the likelihood of unsafe failures, the likelihood of each fault\/defect must be estimated to be able to compute these metrics. The metrics include:<\/p>\n<p>&nbsp;<\/p>\n<ul>\n<li>Single point fault metric <strong>(SPFM)<\/strong><\/li>\n<li>Probabilistic metric for random hardware failures <strong>(PMHF)<\/strong><\/li>\n<li>Residual faults <strong>(DC-Residual)<\/strong><\/li>\n<li>Latent faults<strong> (DC-Latent)<\/strong><\/li>\n<li>Latent fault metric<strong> (LFM)<\/strong><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>All but LFM can be measured by Tessent DefectSim by injecting on defect at a time. LFM cannot be measured by injecting one defect at a time since, by definition, latent defects do not individually cause any failure. With Tessent DefectSim, a two-step procedure is used to overcome this limitation when measuring LFM. Figure 1 shows a simplified Venn diagram of the different outcomes of simulated injected defects.<\/p>\n<p><a href=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/48\/2018\/04\/Blog-figure.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-595\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/48\/2018\/04\/Blog-figure-520x387.jpg\" alt=\"\" width=\"520\" height=\"387\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>Tessent DefectSim automatically measures all these metrics. It can also simulate entirely digital circuits but inject transistor-level defects instead of gate-level stuck-at faults. This allows IC designers to provide an automated and objective assessment of likelihood-weighted defect coverage and defect tolerance, in less time, when these metrics are required by Tier 1 automotive customers.<\/p>\n<p>&nbsp;<\/p>\n<p>For details on how Tessent DefectSim measures the fault metrics for analog circuits, download the whitepaper <a href=\"https:\/\/www.mentor.com\/products\/silicon-yield\/resources\/overview\/measuring-iso-26262-metrics-of-analog-circuitry-in-ics-921b5bb2-5b20-46a8-8f1d-610011868804\/?cmpid=11832\" target=\"_blank\" rel=\"noopener noreferrer\">Measuring ISO 26262 Metrics of Analog Circuitry in ICs<\/a>.<\/p>\n<p><a href=\"http:\/\/bit.ly\/1hf2bMq\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-61 size-full\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/48\/2015\/09\/LinkedIn-Button.jpg\" alt=\"\" width=\"300\" height=\"70\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>By Stephen Sunter\u00a0 &#8211; Mentor, A Siemens Business ICs designed for safety-related automotive systems are expected to operate safely for&#8230;<\/p>\n","protected":false},"author":71644,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spanish_translation":"","french_translation":"","german_translation":"","italian_translation":"","polish_translation":"","japanese_translation":"","chinese_translation":"","footnotes":""},"categories":[1],"tags":[],"industry":[],"product":[],"coauthors":[],"class_list":["post-593","post","type-post","status-publish","format-standard","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/posts\/593","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/users\/71644"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/comments?post=593"}],"version-history":[{"count":1,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/posts\/593\/revisions"}],"predecessor-version":[{"id":2355,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/posts\/593\/revisions\/2355"}],"wp:attachment":[{"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/media?parent=593"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/categories?post=593"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/tags?post=593"},{"taxonomy":"industry","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/industry?post=593"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/product?post=593"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/tessent\/wp-json\/wp\/v2\/coauthors?post=593"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}