液晶电视CAF失效实例分析和预防

电子产品大量使用印制电路板(PCB),在潮湿环境下使用时易产生导电性阳极丝失效,影响电子产品可靠性。通过对多起液晶电视机电路板CAF失效实例的测试、分析,总结出导电性阳极丝失效(即CAF失效)首先发生在具有固定直流偏压的高阻抗电路中,同时分析了CAF失效高发的现象与盐雾之间的关联性,通过对比说明了PCB设计、装配工艺、PCB选材对CAF预防的不同效果,指出了选择抗CAF的PCB材料的重要性,并给出了两种在线监测电路的设计方案。

CAF Failue Cases Analysis and Precaution in LCD TV

Most Printed Circuit Boards are applied to electronic products, failure and unreliable may appear during work in wet environment because of Conductive Anodic Filament (CAF). Some engineering cases are tested and analyzed in this article, it is summarized that CAF failure happen first in the high resistance circuit with DC bias voltage. The Association between CAF and salt fog is analyzed, the different anti-CAF effects of PCB design, PCBA process and PCB material is also indicated in the article. PCB material is pointed out has more importance for anti-CAF, and two electric circuits for CAF detection is given out as a suggestion.