Humidity Control in Electronic Devices: Water Sorption Properties of Desiccants and Related Humidity Build-Up in Enclosures

A common concern with electronics packaging is the reduction of moisture ingress into the devices. One option to consider is the use of water absorption desiccant. Its criteria for selection should be its water capacity property, while its regeneration temperature has to be taken into account. Electronic devices are exposed to all kinds of harsh cyclic environments, and assuring a low level of humidity inside the devices implies the replacement of the desiccant once its saturation content is reached. This may not be applicable, or the frequency of replacement may represent a high cost. Using the dissipated heat from the electronic devices during the “ON” time may be a low-cost process for the regeneration of the desiccant, therefore increasing its lifetime. This article presents the experimental investigation of the performance of different desiccants on water absorption and regeneration. Analysis and test results show that the desiccant system continuously maintains a lower humidity inside the electronic enclosures over the tested time of cyclic exposure if they can be regenerated using device self-heating.