2017-07-13 16:17 来源:未知 阅读次数:
在工作中遇到很多工程师咨询钽电容失效分析和钽电容故障概率等类似的问题,由于钽电容故障概率及钽电容失效分析涉及的因素众多,本文仅仅探讨稳态下贴片钽电容可靠性和故障率的计算方法,以AVX钽电容的TAJ、TPS等常用系列为分析对像。
钽电容介质钽氧化物基本上没有淘汰机制,某些情况下的磨损有自我修复能力(有限的自我修复能力)。然而,在操作中经常会有随机故障的发生。钽电容的故障率与工作时间有非常大的关系,将随时间的缩短而减少
图1。钽电容可靠性曲线
在稳定状态,钽电容的使用寿命的可靠性是由三个因素的影响。计算故障率的方程是:
F = FV xFTx FR xFB
其中:
FV=工作电压修正系数,等于施加电压/额定电压的值
FT=工作温度修正系数,大约等于环境温度\额定工作温度*固定系数.
FR=电路中电阻的修正系数,大约等于电阻\电压*固定系数
FB=基本的故障率水平,一个标准含铅钽电容的基本故障率水平是这是1%/1000小时(100个钽电容工作1000小时出现故障的机率是1个)
以下是AVX官网对钽电容失效分析、钽电容故障概率的原谅,英文好的工程师们可以直接看英文资料。
Tantalum Dielectric has essentially no wear out mechanism and in certain circumstances is capable of limited self healing, random failures can occur in operation. The failure AVX
rate of Tantalum capacitors will decrease with time and not increase as with other electrolytic capacitors and other electronic components
The useful life reliability of the Tantalum capacitor is affected by three factors. The equation from which the failure rate can be calculated is:
F = FU x FT x FR x FB
where FU is a correction factor due to operating voltage/voltage derating
FT is a correction factor due to operating temperature
FR is a correction factor due to circuit series resistance
FB is the basic failure rate level. For standard leaded Tantalum product this is 1%/1000hours