www.sensirion.com / D1

Version 2

– July 2021

4/17

2 Humidity and Temperature Sensor Specifications

Every SHT4x is individually tested and calibrated and is identifiable by its unique serial number

(see section 4.6 for details on the serial number). For the calibration, Sensirion uses transfer

standards, which are subject to a scheduled calibration procedure. The calibration of the reference,

used for the calibration of the transfer standards, is NIST traceable through an ISO/IEC 17025

accredited laboratory.

2.1 Relative Humidity

Parameter

Conditions

Value

Units

SHT40 RH accuracy1

typ.

1.8

%RH

max.

see Figure 2

-

SHT41 RH accuracy1

typ.

1.8

%RH

max.

See Figure 3

-

SHT45 RH accuracy1

typ.

1.5

%RH

max.

tbd

-

Repeatability2, 3

high

0.08

%RH

medium

0.15

%RH

low

0.25

%RH

Resolution4

-

0.01

%RH

Hysteresis

-

1

%RH

Specified range5

extended6

0 to 100

%RH

Response time7

t63%

6

s

Long-term drift8

typ.

<0.25

%RH/y

Table 1: General relative humidity sensor specifications.

Figure 2: SHT40 typical and maximal relative

humidity accuracy at 25 °C.

Figure 3: SHT41 typical and maximal relative

humidity accuracy at 25 °C.

1 For definition of typ. and max. accuracy, please refer to the document “Sensirion Humidity Sensor Specification Statement”.

2 The stated repeatability is 3 times the standard deviation (3σ) of multiple consecutive measurement values at constant conditions and is a measure for the noise

on the physical sensor output. Different repeatability commands are listed in Table 7.

3 Valid for 25°C and 50%RH.

4 Resolution of A/D converter.

5 Specified range refers to the range for which the humidity or temperature sensor specification is guaranteed.

6 For details about recommended humidity and temperature operating range, please refer to section 2.3.

7 Time for achieving 63% of a humidity step function, measured at 25°C and 1 m/s airflow. Humidity response time in the application depends on the design-in of the

sensor.

8 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.

±0

±2

±4

±6

±8

0

10 20 30 40 50 60 70 80 90 100

Relative Humidity (%RH)

SHT40 typ

SHT40 max

DRH (%RH)

±0

±2

±4

±6

±8

0

10 20 30 40 50 60 70 80 90 100

Relative Humidity (%RH)

SHT41 typ

SHT41 max

DRH (%RH)