SHT21 Digital Humidity and Temperature Sensor Product Summary
The SHT21 humidity and temperature sensor of Sensirion has become an industry standard in terms of form factor and intelligence: Embedded in a reflow solderable Dual Flat No leads (DFN) package of 3 x 3mm foot print and 1.1mm height it provides calibrated, linearized sensor signals in digital, I2C format.
The SHT2x sensors contain a capacitive type humidity sensor, a band gap temperature sensor and specialized analog and digital integrated circuit all on a single CMOSens ® chip. This yields in an unmatched sensor performance in terms of accuracy and stability as well as minimal power consumption.
Every sensor is individually calibrated and tested. Lot identification is printed on the sensor and an electronic identification code is stored on the chip which can be read out by command. Furthermore, the resolution of SHT2x can be changed by command (8/12bit up to 12/14bit for RH/T) and a checksum helps to improve communication reliability.
With this set of features and the proven reliability and long-term stability, the SHT2x sensors offer an outstanding performance-to-price ratio. For testing SHT2x two evaluation kits EK-H4 and EK-H5 are available.
SHT21 Digital Humidity and Temperature Sensor FEATURES
Fully calibrated
Digital output, I2C interface
Low power consumption
Excellent long term stability
DFN type package reflow solderable
SHT21 Digital Humidity and Temperature Sensor Performance
Relative Humidity
Parameter | Condition | Value | Units |
Resolution | 12 bit | 0.04 | %RH |
8 bit | 0.7 | %RH | |
Accuracy tolerance | typ | ±2 | %RH |
max | see Figure 2 | %RH | |
Repeatability | ±0.1 | %RH | |
Hysteresis | ±1 | %RH | |
Nonlinearity | <0.1 | %RH | |
Response time | 63% | 8 | s |
Operating Range | extended | 0 to 100 | %RH |
Long Term Drift | Typ. | < 0.25 | %RH/yr |
Temperature
Parameter |
Condition | Value | Units |
Resolution | 14 bit | 0.01 | °C |
12 bit | 0.04 | °C | |
Accuracy tolerance | typ | ±0.3 | °C |
max | see Figure 3 | ||
Repeatability | ±0.1 | °C | |
Operating Range | extended | -40 to 125 | °C |
Response Time | 63% | 5 to 30 | s |
Long Term Drift | Typ. | < 0.02 | °C/yr |
Parameter |
Conditions | min | typ | max | Units |
Supply Voltage, VDD | 2.1 | 3.0 | 3.6 | V | |
Supply Current, IDD | sleep mode | - | 0.15 | 0.4 | µA |
measuring | 200 | 300 | 330 | µA | |
Power Dissipation | sleep mode | - | 0.5 | 1.2 | µW |
measuring | 0.6 | 0.9 | 1.0 | mW | |
average 8bit | - | 3.2 | - | µW | |
Heater | VDD = 3.0 V | 5.5mW, T = + 0.5-1.5°C | |||
Communication | digital 2-wire interface, I2C protocol |
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