A permanent cover is made of hydrophobic microporous PTFE membrane to protect against water and dust according to IP67 specification, and is designed to stay on the package over the product lifetime. This protective cover has a filtration of up to 99.99% efficiency filtering particle sizes down to 100nm. In addition to being water and dust proof per IP67, this PTFE material has extremely high-durability and low-friction to repel water, condensation droplets and debris, while maintaining sensor response time, making it most suitable for outdoor use and rugged environment applications. Figure 1-5 depicts a humidity sensor with a permanent protective cover, the HDC2022, which is pin- and software- compatible with HDC2080 and HDC2021.

Most applications can use non-protective cover humidity sensors because of its robust polymer sensing element. Also, all these sensors are based on the same core and inherently offer some of the lowest power consumption with high and consistent accuracy in the market. If an assembly line cannot provide special flow for standard humidity sensors or a sealed humidity sensing module is desired, then a removable protective cover humidity sensor, like the HDC2021 would be an excellent option. For outdoor use or harsh environment usage, where condensation is likely to occur or volatile organic compounds (VOCs) may be present, the HDC2022 would be the best choice.