Overview
The SHT21S humidity and temperature sensor from Sensirion AG is a widely recognized industry standard for its form factor and intelligence. It is encapsulated in a reflow solderable Dual Flat No leads (DFN) package with a footprint of 3 x 3 mm and a height of 1.1 mm. This sensor provides calibrated, linearized sensor signals in both digital I2C and analog Sigma Delta Modulated (SDM) formats. The SHT21S features a generation 4C CMOSens® chip, which includes a capacitive relative humidity sensor, a band gap temperature sensor, an amplifier, an A/D converter, OTP memory, and a digital processing unit. Each sensor is individually calibrated and tested, ensuring high accuracy and reliability.
Key Specifications
| Parameter | Value | Units |
|---|---|---|
| Humidity Range | 0 - 100 | % RH |
| Humidity Accuracy | ±2.0 | % RH |
| Temperature Accuracy | ±0.3 | °C |
| Humidity Resolution | 12 bit (0.04 % RH) | |
| Response Time (τ63%) - Humidity | 8 | s |
| Response Time (τ63%) - Temperature | 30 | s |
| Operating Temperature Range | -40 to 125 | °C |
| Supply Voltage | 2.1 - 3.6 | V |
| Average Supply Current | 160 | μA |
| Interface Type | I2C, SDM |
Key Features
- Fully calibrated and linearized sensor signals
- Digital output via I2C interface, and analog output via Sigma Delta Modulated (SDM) signal
- Low power consumption with an average supply current of 160 μA
- Excellent long-term stability and accuracy
- Reflow solderable DFN package with a footprint of 3 x 3 mm and a height of 1.1 mm
- RoHS and WEEE compliant, free of Pb, Cd, and Hg
- Individual calibration and testing for each sensor
- Checksum for improved communication reliability
Applications
The SHT21S is versatile and can be used in a variety of applications, including:
- Environmental monitoring systems
- Industrial automation and control systems
- Agricultural and greenhouse monitoring
- Weather stations and meteorological equipment
- Medical devices and healthcare equipment
- Consumer electronics such as smart home devices and wearables
Q & A
- What is the humidity range of the SHT21S sensor?
The SHT21S sensor measures humidity in the range of 0 to 100% relative humidity (% RH).
- What is the accuracy of the humidity measurements?
The humidity accuracy is typically ±2.0% RH.
- What is the temperature accuracy of the SHT21S sensor?
The temperature accuracy is typically ±0.3°C.
- What are the response times for humidity and temperature measurements?
The response time for humidity is 8 seconds (τ63%), and for temperature, it is 30 seconds (τ63%).
- What is the operating temperature range of the SHT21S sensor?
The operating temperature range is from -40°C to 125°C.
- What are the power supply requirements for the SHT21S sensor?
The supply voltage range is 2.1 to 3.6 V, with a recommended supply voltage of 3.0 V.
- Is the SHT21S sensor RoHS compliant?
- What interfaces does the SHT21S sensor support?
The sensor supports both I2C and SDM interfaces.
- How is the sensor calibrated?
- What is the average supply current of the SHT21S sensor?
