The Sensirion SHT2x series of DFN digital humidity & temperature sensors are CMOSens® based. They are an industry standard, widely used humidity and temperature sensor. Humidity is measured using a capacitive sensor while temperature is measured using a band-gap sensor.
The SHT2x sensors also contain a version 4 silicon chip with an amplifier, A/D converter, OTP memory and a digital interface. They come in a plastic package which leaves the sensor area open, protecting the devices from external impact and providing long-term stability.
SHT2x sensors are ideal for both high and low volume applications.
The SHT21P has a PWM output and the SHT21S has a PDM output; these can be converted into analogue outputs by the use of suitable low-pass filters.
SHT20 - Low cost, SHT21 - Standard, SHT25 - High Accuracy

CMOSens® based technology
Fully calibrated
I²C serial interface (Not SHT21P/SHT21S)
Digital output
Low power consumption
Long-term stability
Supply voltage range: 2.1 to 3.6 V

123-7351 · SHT20 · I²C Digital output
786-5554 · SHT21 · I²C Digital output
876-5055 · SHT21P · PWM output
876-5064 · SHT21S · PDM output
727-6226 · SHT25 · I²C Digital output

Temperature & Humidity Sensors, Sensirion