HTU21D Digital Relative Humidity Sensor TE Connectivity's (TE) Measurement Specialties HTU21D Digital Relative Humidity Sensor is embedded in a reflow solderable Dual Flat No leads (DFN) package with a 3 x 3mm foot print and 1mm height. TE's HTU21D provides calibrated, linearized signals in a digital, I2C format. HTU21D sensors are dedicated humidity and temperature plug-and-play transducers for OEM applications. Direct interface with a micro-controller is enabled with the modular humidity and temperature digital outputs.