Accelerated Tests for the Effects of Power Cycling on Tantalum Capacitors in a Humid Environment

摘要

Power cycling may occur in electrical devices used in the field, and it may often take place in a humid environment with high temperature, further accelerating stress effects. This study focuses on testing the effects of power cycling; especially the effects of a single off period on surface mount tantalum capacitors in a humid environment. First, the effects of temperature and humidity on tantalum capacitors are introduced. Research was done by using the standard 85/85 test and new kind of power cycling tests that were developed based on the 85/85 test. These new tests were done in 85/85 conditions, with a single power off period of 70 h in the beginning of a test or in the middle of a test. Also, the moisture absorption of tantalum capacitors was examined. The moisture absorption results show that when the devices are off, they absorb moisture faster than when they are on. The accelerated test results suggest that humidity is absorbed during a high humidity/high temperature test, especially during the off period, and catastrophic failures occur when devices are turned on afterward. The new kind of reliability tests that were developed on the basis of the standard 85/85 test could be efficiently used for examining the effects of power cycling in a humid environment.