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Version 0.91 – October 2010

3/12

Users Guide SHT25ss

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 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

RH accuracy at various temperatures

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.

100

±5 ±5 ±5 ±5 ±5 ±4 ±5 ±5 ±5 ±5 ±5 ±5 ±5 ±5 ±6 ±8 ±10

±5 ±5 ±5 ±4 ±4 ±3 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±5 ±5 ±6 ±8

90

±5 ±5 ±4 ±3 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±4 ±4 ±4 ±5 ±6 ±8

±5 ±4 ±4 ±3 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±4 ±4 ±4 ±5 ±6 ±8

80

±4 ±4 ±4 ±3 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±3 ±3 ±4 ±4 ±5 ±6

±4 ±4 ±4 ±3 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±4 ±5 ±6

70

±4 ±4 ±4 ±3 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±4 ±5 ±6

±4 ±4 ±3 ±3 ±2 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±3 ±3 ±4 ±5 ±6

60

±4 ±3 ±3 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±5

±4 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±5

50

±4 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±5

±4 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±4

40

±4 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±4

±4 ±3 ±3 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±4

30

±4 ±3 ±3 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±4

±4 ±4 ±3 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±3 ±3 ±4 ±4

20

±4 ±4 ±4 ±3 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±3 ±4 ±4

±5 ±4 ±4 ±3 ±2 ±2 ±2 ±3 ±3 ±3 ±3 ±3 ±4 ±4 ±4 ±4 ±5

10

±8 ±5 ±5 ±4 ±3 ±2 ±3 ±4 ±4 ±4 ±4 ±4 ±4 ±4 ±5 ±6 ±8

±8 ±8 ±8 ±6 ±5 ±3 ±5 ±5 ±5 ±5 ±5 ±5 ±5 ±5 ±6 ±8 ±10

0

10

20

30

40

50

60

70

80

Temperature (°C)

Figure 5 Maximal tolerance of relative humidity measurements

given in %RH for temperatures 0 – 80°C

.

Please note that above values are maximal tolerances (not

including hysteresis) against a high precision reference

such as a dew point mirror.

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 Dependency of supply current (sleep mode) versus

temperature at VDD = 3.0V. Please note the variance of the

displayed data may exceed ±25%.

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 the variance of the

displayed data may exceed ±25%.

0

20

40

60

80

100

-40

-20

0

20

40

60

80

100

120

Temperature (°C)

Max.

Range

Normal

Range