SHT21 SENSIRION, SHT21 Datasheet - Page 3

• Manufacturer Part Number: SHT21
• Description: Humidity/Temperture Sensor
• Manufacturer: SENSIRION

Specifications of SHT21

• Operating Temperature Range: -40°C To +125°C
• No. Of Pins: 6
• Supply Voltage: 3V
• Humidity Sensor Type: Capacitive
• Sensor Case Style: DFN
• Humidity Range: 0% To 100%
• Response Time: 8s
• Accuracy: ± 2%
• Supply Current: 300µA

Datasheet SHT21
Users Guide SHT2x
1 Extended Specification
For details on how Sensirion is specifying and testing
accuracy performance please consult Application Note
“Statement on Sensor Specification”.
1.1
The sensor works stable within recommended Normal
Range – see Figure 4. Long term exposure to conditions
outside Normal Range, especially at humidity >80%RH,
may temporarily offset the RH signal (+3%RH after 60h).
After return into the Normal Range it will slowly return
towards calibration state by itself. See Section 2.3
“Reconditioning Procedure” for eliminating the offset.
Prolonged exposure to extreme conditions may accelerate
ageing.
Figure 4 Operating Conditions
1.2
Maximal tolerance for RH accuracy at 25°C is defined in
Figure 2. For other temperatures maximal tolerance has
been evaluated to be within limits displayed in Figure 5.
Figure 5 Maximal tolerance of relative humidity measurements
given in %RH for temperatures 0 – 80°C.
www.sensirion.com
100
100
80
60
40
20
90
80
70
60
50
40
30
20
10
0
0
Operating Range
RH accuracy at various temperatures
-40
±6
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
±4
±6
-20
±5
±3
±5
0
±5
±4
±3
±4
±5
20
Normal
Range
±5
±5
40
±3
60
±7
Temperature (°C)
Temperature (°C)
±4
Max.
Range
80
±7
±6
100
±8
Version 1.1 – May 2010
120
Please note that above values are maximal tolerances (not
including hysteresis) against a high precision reference
such as a dew point mirror. Typical deviations are at
±2%RH where maximal tolerance is ±3%RH and about
half the maximal tolerance at other values.
1.3
Current consumption as given in Table 1 is dependent on
temperature and supply voltage VDD. For estimations on
energy consumption of the sensor Figures 6 and 7 may be
consulted. Please note that values given in these Figures
are of typical nature and the variance is considerable.
Figure 6 Typical dependency of supply current (sleep mode)
versus temperature at VDD = 3.0V. Please note that the
variance of these data is about ±25% of displayed value.
Figure 7 Typical dependency of supply current (sleep mode)
versus supply voltage at 25°C. Please note that deviations may
be up to ±50% of displayed value. Values at 60°C scale with a
factor of about 15 (compare Table 1).
Electrical Specification
8
7
6
5
4
3
2
1
0
20
18
16
14
12
10
8
6
0
2.1
2.3
20
2.5
40
2.7
60
2.9
Supply Voltage (VDD)
80
3.1
Temperature (°C)
100
3.3
3.5
120
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