Datasheet

www.sensirion.com Version 1.1 – May 2010 2/12
Sensor Performance
Relative Humidity
1234
Parameter Condition min typ max Units
12 bit 0.04 %RH
Resolution
1
8 bit 0.7 %RH
typ
2.0
%RH
Accuracy
tolerance
2
max see Figure 2 %RH
Repeatability
0.1
%RH
Hysteresis
1
%RH
Nonlinearity <0.1 %RH
Response time
3
 63%
8 s
Operating Range extended
4
0 100 %RH
Long Term Drift
5
normal < 0.5 %RH/yr
± 0
± 2
± 4
± 6
± 8
± 10
0 10 20 30 40 50 60 70 80 90 100
Relative Humidity (%RH)

RH (%RH)
maximal tolerance
typical tolerance
Figure 2 Typical and maximal tolerance at 25°C for relative
humidity. For extensive information see Users Guide, Sect. 1.2.
Electrical Specification
Parameter Conditions min typ max Units
Supply Voltage, VDD 2.1 3.0 3.6 V
sleep mode
- 0.15 0.4 µA
Supply Current, IDD
6
measuring
270 300 330 µA
sleep mode
- 0.5 1.2 µW
measuring
0.8 0.9 1.0 mW
Power Dissipation
6
average 8bit
- 3.2 - µW
Heater
VDD = 3.0 V
5.5mW, T = + 0.5-1.5°C
Communication digital 2-wire interface, true I
2
C protocol
Table 1 Electrical specification. For absolute maximum
values see Section 4.1 of Users Guide.
1
Default measurement resolution is 14bit (temperature) / 12bit (humidity). It can
be reduced to 12/8bit, 11/11bit or 13/10bit by command to user register.
2
Accuracies are tested at Outgoing Quality Control at 25°C (77°F) and 3.0V.
Values exclude hysteresis and long term drift and are applicable to non-
condensing environments only.
3
Time for achieving 63% of a step function, valid at 25°C and 1m/s airflow.
4
Normal operating range: 0-80%RH, beyond this limit sensor may read a
reversible offset with slow kinetics (<3%RH after 200hours at 90%RH). For more
details please see Section 1.1 of the Users Guide.
Temperature
567
Parameter Condition min typ max Units
14 bit 0.01 °C
Resolution
1
12 bit 0.04 °C
typ
0.3
°C
Accuracy
tolerance
2
max see Figure 3 °C
Repeatability
0.1
°C
-40 125 °C
Operating Range extended
4
-40 257 °F
Response Time
7
 63%
5 30 s
Long Term Drift < 0.04 °C/yr
± 0.0
± 0.5
± 1.0
± 1.5
± 2.0
± 2.5
± 3.0
-40 -20 0 20 40 60 80 100 120
Temperature (°C)

T (°C)
maximal tolerance
typical tolerance
Figure 3 Maximal tolerance for temperature sensor in °C.
Packaging Information
Sensor Type Packaging Quantity Order Number
Tape & Reel 400 1-100707-01
Tape & Reel 1500 1-100645-01
SHT21
Tape & Reel 5000 1-100694-01
This datasheet is subject to change and may be amended
without prior notice.
5
Value may be higher in environments with vaporized solvents, out-gassing
tapes, adhesives, packaging materials, etc. For more details please refer to
Handling Instructions.
6
Min and max values of Supply Current and Power Dissipation are based on
fixed VDD = 3.0V and T<60°C. The average value is based on one 8bit
measurement per second.
7
Response time depends on heat conductivity of sensor substrate.