IGBT失效率FIT和平均无故障时间MTBF的定义
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
A PPLICATION
N OTE Page 1 von 2
eupec GmbH + Co KG Max-Planck-Straße 5D-59581 Warstein Tel. +49(0)2902 764-0Fax +49(0)2902 764-1256EMail info@
An Infineon Technologies Company Definition of FIT and MTBF
A failure rate λ=is defined by the number of failures r during a specific test time t of n components:
The unit for failure rates is 1 fit (f ailures i n t ime) = 1*10-9h -1,meaning one failure in 109 operation hours of the device.
A component specified with 100 fit is therefore expected to operate 107 hours.
Example: Testing 4000 components for 5000 hours with 2 failures in this time leads to a failure rate of
The failure rate or fit value is used to calculate the MTBF (m ean t ime b etween f ailures) of a complete equipment existing of i separate components with individual failure rates λi :MTBF = 1 / Σ λi
Example: An equipment is built of 50 components with 250 fit each, which adds up to a MTBF of 1 / (50×250fit) = 80.000 h. The equipment is operated 18 hours a day and 300 days a year under the specified operating conditions. The expected lifetime is therefore: 80.000 h / (300*18 h) = 14.8 years.t n r
⋅=λfit fit h h h
10010101015000*40002197
1
7==⋅==−−−−−λ or expressed in fit:
F
IT-R ATES FOR IGBT M ODULES Page 2 of 2
Together with the fit value, the operating conditions must be given. For eupec IGBT modules these conditions are: operation at 50% nominal voltage, 50% nominal current and Tamb = 40°C.Tracing back shipped modules, estimated accumulated operation hours and field returns for the last years, we could calculate the following tendency in the failure rates: