星载大功率GaN固态功放寿命评估方法

近年来大功率氮化镓（GaN）固态功放开始逐步星载应用，但产品可靠性仍未得到充分验证。文章提出利用加速寿命试验（ALT）和在轨工作情况相结合的方法进行大功率GaN固态功放寿命评估。首先利用故障模式、机理及影响分析（FMMEA）确定固态功放的薄弱环节和主要失效机理；然后基于阿仑尼乌斯（Arrhenius）模型研究加速寿命试验激活能和加速应力的取值方法，对产品进行75 ℃、10 000 h的加速寿命试验；最后综合加速寿命试验结果和在轨工作情况对GaN固态功放进行寿命评估。评估结果显示:该产品45 ℃条件下在轨工作时，平均无故障时间（MTTF）为1.26×106 h，失效率为7.93×10-7，15年工作可靠度为0.901。

Method for life evaluation of spaceborne high power GaN solid state power amplifier

In recent years, the high-power gallium nitride (GaN) solid-state power amplifiers (SSPA) have gradually been put into aerospace applications, but their reliability is still to be verified. This paper proposes a method for evaluating the lifetime of the high-power GaN SSPA through the accelerated life test (ALT), as well as their on-orbit working performance. First, the weakness and the main failure mechanisms of the GaN SSPA are analyzed, including the failure mode, mechanisms and effects analysis (FMMEA). Then, a method of determining the value of the activation energy and the accelerated stress is discussed, based on the Arrhenius model. At the same time, an ALT of 75 ℃ with a duration of 10 000 h is carried out. Finally, based on the test results and the on-orbit performance, a series of deduced results are obtained under the normal working condition of 45 ℃ which illustrate that the mean time to failure (MTTF) is 1.26×106 h, while the failure rate is 7.93×10-7, and the working reliability of 15 years is 0.901.