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Product Summary
As a new generation of temperature and humidity sensors, AHT21 sets a new standard in terms of size and
performance: a two-row flat pin less SMD package suitable for reflow soldering, bottom face 3x3mm, height 0.8mm.The
sensor outputs calibrated digital signals in standard IIC format.
AHT21 is equipped with a newly designed ASIC dedicated chip, an improved MEMS semiconductor capacitive humidity
sensor element and a standard on-chip temperature sensor element. Its performance has been greatly improved or even
exceeded the reliability level of the previous generation of sensors. A generation of temperature and humidity sensors
have been improved to make their performance more stable in harsh environments.
Each sensor is calibrated and tested, and the product lot number is printed on the surface of the product. Due to
improvements and miniaturization of the sensor, it is more cost-effective, and ultimately all devices will benefit from
cutting-edge energy-saving operation modes.
Data Sheet AHT21
Humidity and Temperature Sensor
• Full calibration
• Digital output, I
2
C interface
• Excellent long-term stability
• SMD package suitable for reflow soldering
• Quick response and strong anti-jamming capability
1 Product Description
The AHT21 can be widely used in consumer electronics, medical, automotive, industrial, meteorological
and other fields, such as: HVAC, dehumidifiers and refrigerators and other home appliances, testing and
testing equipment and other related temperature and humidity detection and control products.
Figure 1. AHT21 Sensor Package Diagram (Unit: mm Tolerance: ±0.1 mm).
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Version:V1.0 —— May 2021
AHT21 Data Sheet
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2 Sensor Specifications
Relative Humidity
Table 1. Humidity characteristics table.
Temperature
Table 2. Temperature Characteristic table
.
Figure 2. Typical and maximum error in relative humidity at 25° C Figure 3. Typical and maximum temperature errors
Parameter
condition
min
typical
max
unit
resolution
Typical
-
0.024
-
%RH
Accuracy error
1
Typical
-
±2
-
%RH
max
See Figure 2
-
%RH
repeatable
-
-
±0.1
-
%RH
hysteresis
-
-
±1
-
%RH
nonlinear
-
-
<0.1
-
%RH
Response time
2
τ 63%
-
8
-
s
Scope of work
Extended
3
0
-
100
%RH
Prolonged Drift
4
-
-
<1
-
%RH /yr
Parameter
condition
min
typical
max
unit
resolution
Typical
-
0.01
-
℃
Accuracy
Error
1
Typical
-
±0.3
-
℃
max
See Figure 3
-
℃
repeatable
-
-
±0.1
-
℃
hysteresis
-
-
±0.1
-
℃
Response time
6
τ 63%
5
30
S
Scope of work
Extended
3
-40
-
120
℃
Prolonged Drift
-
-
<0.1
-
℃/yr