欢迎来到麦多课文档分享! | 帮助中心 海量文档,免费浏览,给你所需,享你所想!
麦多课文档分享
全部分类
  • 标准规范>
  • 教学课件>
  • 考试资料>
  • 办公文档>
  • 学术论文>
  • 行业资料>
  • 易语言源码>
  • ImageVerifierCode 换一换
    首页 麦多课文档分享 > 资源分类 > PDF文档下载
    分享到微信 分享到微博 分享到QQ空间

    REG NASA-LLIS-0703-2000 Lessons Learned - Part Junction Temperature.pdf

    • 资源ID:1018349       资源大小:20.76KB        全文页数:5页
    • 资源格式: PDF        下载积分:10000积分
    快捷下载 游客一键下载
    账号登录下载
    微信登录下载
    二维码
    微信扫一扫登录
    下载资源需要10000积分(如需开发票,请勿充值!)
    邮箱/手机:
    温馨提示:
    如需开发票,请勿充值!快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。
    如需开发票,请勿充值!如填写123,账号就是123,密码也是123。
    支付方式: 支付宝扫码支付    微信扫码支付   
    验证码:   换一换

    加入VIP,交流精品资源
     
    账号:
    密码:
    验证码:   换一换
      忘记密码?
        
    友情提示
    2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网页到桌面,就可以正常下载了。
    3、本站不支持迅雷下载,请使用电脑自带的IE浏览器,或者360浏览器、谷歌浏览器下载即可。
    4、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰。
    5、试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。

    REG NASA-LLIS-0703-2000 Lessons Learned - Part Junction Temperature.pdf

    1、Best Practices Entry: Best Practice Info:a71 Committee Approval Date: 2000-03-15a71 Center Point of Contact: JPLa71 Submitted by: Wil HarkinsSubject: Part Junction Temperature Practice: Maintain part junction temperatures during flight below 60C. (Short-term mission excursions associated with transi

    2、ent mission events are permissible.)Abstract: Preferred Practice for Design from NASA Technical Memorandum 4322A, NASA Reliability Preferred Practices for Design and Test.Benefit:Reliability is greatly increased because the failure rate is directly related to the long-term flight Provided by IHSNot

    3、for ResaleNo reproduction or networking permitted without license from IHS-,-,-temperature.Implementation Method:Establish in-specification design (and test) temperatures 75C and limit part junction temperatures (JT) to 110C which constrains permissible part junction temperature rise (DJT) to 35C. (

    4、This practice has been verified on programs in place before the release of MIL-STD-975H. If the MIL-STD-975H junction temperature of 100C is used, junction temperature rise should be changed to assure that long-term flight junctions stay below 60C.)Technical Rationale:Basic reliability is directly r

    5、elated to temperature and time, i.e., l = f(T,t). The following relationship is obtained either theoretically from the Arrhenius relationship (l= Aexp-Ea/k (1/T - 1/T0) or empirically from the data in MIL-HDBK-217E.refer to D description DGiven: a71 Specific parta71 Specific derating factora71 Speci

    6、fic chemical activation energyThe curve shape is representative of all electronic parts (and most mechanical processes) in the range of temperature typified by space exposure. Simply stated, the higher the long-term flight temperatures, the lower the reliability:refer to D descriptionD Assume that a

    7、 design and test temperature of 75C is chosen. In the graph from MIL-STD-883B observe that a 25C D T corresponds to a failure rate increase of more than an order of magnitude- i.e., 1000% difference. MIL-HDBK-217E has different values, but the factor is up to approximately Provided by IHSNot for Res

    8、aleNo reproduction or networking permitted without license from IHS-,-,-3X on some parts (depends on derating criteria and parts qualification). The following example illustrates the effect of this relationship on design and test temperatures.Assume the following conditions as an example:Case A: T =

    9、 75C in-specification design temperature for baseplateCase B: T = 50C in-specification design temperature for baseplateCase A and Case B: T = 25C long-duration flight temperature for baseplateJT= 110C limit for any exposure or analysisThen:Design/Test Parameters Case A Case BDesign Baseplate 75C 50C

    10、 JTlimit110C 110C Permitted DJTrise35C 60C Flight Conditions refer to D descriptionD from Arrhenius Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-refer to D descriptionD NOTE: In the example given, short-term ground test exposure on the order of 1-

    11、2 weeks will use an insignificant amount of life in hardware designed for long-life and high reliability. For example, a 1-week thermal vacuum test at 75C provides a short-term high temperature screen in the actual circuit usage configuration to provide confidence for a long-term exposure under flig

    12、ht conditions (JT60C), and uses only 0.018% of the parts capability. This demonstration is an important element in establishing pre-launch confidence in design adequacy.refer to D descriptionD (Click image for a larger view) References:1. Gibbel, M. and Clawson, J.F., “Electronic Assembly Thermal Te

    13、sting Dwell/Duration/Cycling,“ Proceeding of the 12th Aerospace Testing Seminar, March 13-15, 1990.2. Gibbel, M. And Cornford, S.L., “Surface Mount Technology Qualification Methodology (Testing and Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Veri

    14、fication),“ Proceeding of the NASA Surface Mount Technology Workshop, NASA Lyndon B. Johnson Space Center, Houston, Texas, July 28-29, 1992.3. Thermal Design Practices for Electronic Assemblies, Reliability Preferred Practice No. PD-ED-1226Impact of Non-Practice: Reliability of electronic parts will

    15、 be reduced significantly if junction temperatures exceed 60C.Related Practices: N/AAdditional Info: Approval Info: a71 Approval Date: 2000-03-15a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-


    注意事项

    本文(REG NASA-LLIS-0703-2000 Lessons Learned - Part Junction Temperature.pdf)为本站会员(arrownail386)主动上传,麦多课文档分享仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文档分享(点击联系客服),我们立即给予删除!




    关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

    copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
    备案/许可证编号:苏ICP备17064731号-1 

    收起
    展开