www.sensirion.com

Version 5 – October 2022

3/14

Users Guide SHT21

1 Extended Specification

For details on how Sensirion is specifying and testing

accuracy performance please consult Application Note

“Statement on Sensor Specification”.

1.1

Operating Range

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 60 h).

After return into the Normal Range it will slowly return

towards calibration state by itself. Prolonged exposure to

extreme conditions may accelerate ageing.

Figure 4 Operating Conditions

1.2

RH accuracy at various temperatures

Typical RH accuracy at 25°C is defined in Figure 2. For

other temperatures, typical accuracy has been evaluated

to be as displayed in Figure 5.

100 ±3.5 ±3

±3

±3

±3

±3 ±3.5 ±4

±4

90 ±3.5 ±3 ±2.5 ±2.5 ±2.5 ±2.5 ±3 ±3.5 ±4

80

±3 ±2.5 ±2

±2

±2 ±2.5 ±2.5 ±3 ±3.5

70

±3 ±2.5 ±2

±2

±2

±2 ±2.5 ±2.5 ±3

60 ±2.5 ±2

±2

±2

±2

±2

±2 ±2.5 ±2.5

50 ±2.5 ±2

±2

±2

±2

±2

±2

±2 ±2.5

40 ±2.5 ±2

±2

±2

±2

±2

±2

±2

±2

30 ±2.5 ±2

±2

±2

±2

±2

±2

±2

±2

20 ±2.5 ±2.5 ±2

±2

±2

±2

±2

±2

±2

10

±3

±3 ±2.5 ±2.5 ±2.5 ±2.5 ±2.5 ±2.5 ±2.5

0 ±3.5 ±3.5 ±3

±3

±3

±3

±3

±3

±3

0

10

20

30

40

50

60

70

80

Temperature [°C]

Figure 5 Typical accuracy of relative humidity measurements

given in %RH for temperatures 0 – 80°C.

1.3

Electrical Specification

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.

0

1

2

3

4

5

6

7

8

0

20

40

60

80

100

120

Temperature (°C)

Figure 6 Typical dependency of supply current (sleep mode)

versus temperature at VDD = 3.0 V. Please note that the

variance of these data can be above ±25% of displayed value.

6

8

10

12

14

16

18

20

2.1

2.3

2.5

2.7

2.9

3.1

3.3

3.5

Supply Voltage (VDD)

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).

0

20

40

60

80

100

-40

-20

0

20

40

60

80

100

120

Temperature (°C)

Max.

Range

Normal

Range