Typical failure mechanisms and precautions of the plastic optocouplers

Optocouplers are widely used in power supply, measuring, controlling and communication products. The field failure rate of plastic optocouplers is usually greater than other semiconductor devices. Analyzing the intrinsic failure mechanisms will help to conduct the component selection, product design and failure precautions. Properties of the package structure and manufacturing processes of the plastic optocouplers have been studied and explored. Typical failure mechanisms with analysis procedures are demonstrated and summarized by some failure cases. Some useful skills and methods for component selection and failure precautions are put forward. These skills and methods will help to eliminate majority failures and thus can improve the application reliability.