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Version 5 – October 2022

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Sensor Performance

Relative Humidity1234

Parameter

Condition

Value

Units

Resolution 1

12 bit

0.04

%RH

8 bit

0.7

%RH

Accuracy tolerance 2

typ

2

%RH

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 to 100

%RH

Long Term Drift 5

Typ.

< 0.25

%RH/yr

± 0

± 2

± 4

± 6

± 8

± 10

0

10

20

30

40

50

60

70

80

90

100

Relative Humidity (%RH)

DRH (%RH)

maximum accuracy

typical accuracy

Figure 2 Typical and maximal tolerance at 25°C for relative

humidity. For extensive information see Users Guide, Sect. 1.2.

Electrical Specification

Parameter

Condition

min

typ

max Units

Supply Voltage, VDD

2.1

3.0

3.6

V

Supply Current, IDD 6

sleep mode

0.15

0.4

µA

measuring

200

300

330

µA

Power Dissipation 6

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,

DT = + 0.5-1.5°C

Communication

digital 2-wire interface, I2C protocol

Table 1 Electrical specification. For absolute maximum values

see Section 4.1 of Users Guide.

1 Default measurement resolution is 14 bit (temperature) / 12 bit (humidity). It

can be reduced to 12/8 bit, 11/11 bit or 13/10 bit by command to user register.

2 Accuracies are tested at Outgoing Quality Control at 25°C and 3.0 V. 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 1 m/s airflow.

4 Normal operating range: 0-80 %RH, beyond this limit sensor may read a

reversible offset with slow kinetics (+3 %RH after 60 h at humidity >80 %RH).

For more details please see Section 1.1 of the Users Guide.

Temperature567

Parameter

Condition

Value

Units

Resolution 1

14 bit

0.01

°C

12 bit

0.04

°C

Accuracy tolerance 2

typ

0.3

°C

max

see Figure 3

Repeatability

0.1

°C

Operating Range

extended 4

-40 to 125

°C

Response Time 7

 63%

5 to 30

s

Long Term Drift 8

Typ.

< 0.02

°C/yr

± 0.0

± 0.5

± 1.0

± 1.5

± 2.0

-40

-20

0

20

40

60

80

100

120

Temperature (°C)

DT (°C)

maximum accuracy

typical accuracy

Figure 3 Typical and maximal tolerance for temperature sensor

in °C.

Packaging Information

Sensor Type

Packaging

Quantity

Order Number

SHT21

Tape & Reel

400

1-100707-01

Tape & Reel

1500

1-100645-01

Tape & Reel

5000

1-100694-01

Please Note: This datasheet is subject to change and may

be amended without prior notice

5 Typical value for operation in normal RH/T operating range. Max. value is <

0.5 %RH/y. 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 = 3.0 V 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.

8 Max. value is < 0.04°C/y.