Datasheet SHT3x-DIS
Humidity and Temperature Sensor
 Fully calibrated, linearized, and temperaturecompensated digital output
 Wide supply voltage range, from 2.4 V to 5.5 V
 I2C Interface with communication speeds up to 1
MHz and two user selectable addresses
 Typical accuracy of  1.5 % RH and  0.2 °C for
SHT35
 Very fast start-up and measurement time Tiny 8-Pin DFN package

Product Summary
SHT3x-DIS is the next generation of Sensirion’s
temperature and humidity sensors. It builds on a new
CMOSens® sensor chip that is at the heart of Sensirion’s
new humidity and temperature platform. The SHT3x-DIS
has increased intelligence, reliability and improved
accuracy specifications compared to its predecessor. Its
functionality includes enhanced signal processing, twodistinctive and user selectable I2C addresses andcommunication speeds of up to 1 MHz. The DFN

package has a footprint of 2.5 x 2.5 mm 2 while keepinga height of 0.9 mm. This allows for integration of the
SHT3x-DIS into a great variety of applications.
Additionally, the wide supply voltage range of 2.4 V to
5.5 V guarantees compatibility with diverse assembly
situations. All in all, the SHT3x-DIS incorporates 15
years of knowledge of Sensirion, the leader in thehumidity sensor industry.

Benefits of Sensirion’s CMOSens® Technology
High reliability and long-term stabilityIndustry-proven technology with a track record of
more than 15 years



Designed for mass productionHigh process capabilityHigh signal-to-noise ratio

nRESET
RH Sensor T Sensor

ADC
ADC

VDD

Power on
Reset

VSS

Calibration
MemoryContent

RESET

1

Sensor Performance.................................................. 2

Data processing& Linearization

2

Specifications.............................................................. 6

Digital Interface

Alert Logic

3

Pin Assignment........................................................... 84

Operation and Communication ................................ 95

Packaging..................................................................15

6

Shipping Package ....................................................17

7

Quality ........................................................................18

8

Ordering Information................................................18

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ADDR

SDA SCL

Alert

Figure 1 Functional block diagram of the SHT3x-DIS. The
sensor signals for humidity and temperature are factory
calibrated, linearized and compensated for temperatur eand supply voltage dependencies.

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Datasheet SHT3x-DIS

1

Sensor Performance

Humidity Sensor Specification
Parameter
SHT30 Accuracy tolerance1
SHT31 Accuracy tolerance1
SHT35 Accuracy tolerance1
Repeatability 2
Resolution
Hysteresis
Specified range3
Response time5
Long-term drift

Condition

Value

Units

Typ.
Max.
Typ.
Max.
Typ.
Max.
Low
MediumHigh
Typ.
at 25°C
extended4
63%
Typ.7

3
Figure 2
2
Figure 3±1.5
Figure 4
0.25
0.15
0.10
0.01
0.8
0 to 100
86
<0.25

% RH
% RH
% RH
% RH
% RH
% RH
% RH
% RH
% RH
s
% RH/yr

Table 1 Humidity sensor specification.

Temperature Sensor Specification
Parameter

Condition

Value

Units

SHT30 Accuracy tolerance1

typ., 0°C to 65°C

0.3

°C

SHT31 Accuracy tolerance1

typ., -40°C to 90°C
typ., -40°C to 90°C

0.3
±0.2

°C

SHT35 Accuracy tolerance1

°C

Low

0.24

°C

Repeatability 2

Medium
High

0.12
0.06

°C
°C

Resolution

Typ.

0.015

°C

Specified Range--40 to 125°C

Response time 8

63%
max

>2

s

<0.03

°C/yr

Long Term Drift
Table 2 Temperature sensor specification .

1 For definition of ty pical and maxim um accuracy tolerance, please refer to the document “Sensirion Humidity Sensor Specification Statement”.
2 The stated repeatability is 3 times the standard deviation (3σ) of multiple consecutive measurements at the stated repeatability and at constant ambient conditions. It

is a measure for the noise on the phy sical sensor output. Different measurement modes allow for high/medium/low repeatability .
3 Specified range refers to the range for w hich the humidity or temperature sensor specification is guaranteed.
4 For details about recommended humidity and temperature operating range, please refer to section 1.1.
5 Time for achiev ing 63% of a humidity step function, valid at 25°C and 1m/s airflow. Humidity response time in the application depends on the design-in of the sensor.
6 With activ ated ART function (see section 4.7) the response time can be improved by a factor of 2.
7 Ty pical value for operation in normal RH/T operating range, see section 1.1. Maximum value is < 0.5 %RH/yr. Higher drift values might occur due to contaminantenv ironments with vaporized solv ents, out-gassing tapes, adhesiv es, packaging materials, etc. For more details please refer to Handling Instructions.
8 Temperature response times strongly depend on the ty pe of heat ex change, the av ailable sensor surface and the design environment of the sensor in the final
application.

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Datasheet SHT3x-DIS

Humidity Sensor Performance Graphs
DRH (%RH)±8±8maximal tolerance
typical tolerance±6

DRH (%RH)
maximal tolerance
typical tolerance

±6

±4

±4

±2

±2

±0

±0
0

10

20

30

40

50

0
10
SHT31

60 70 80 90 100
Relative Humidity (%RH)

SHT30

Figure 2 Tolerance of RH at 25°C for SHT30.

20

30

40

50

60 70 80 90 100
Relative Humidity (%RH)

Figure 3 Tolerance of RH at 25°C for SHT31.

DRH (%RH)±6maximal tolerance
typical tolerance
±4

±2

±0
0
10
SHT35

20

30

40

50

60 70 80 90 100
Relative Humidity (%RH)

Figure 4 Tolerance of RH at 25°C for SHT35.

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Datasheet SHT3x-DIS
SHT30

SHT31

RH (%RH)
100 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5
90 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±380 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±370 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±360 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±350 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±340 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±330 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±320 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±3
10 ±3
±3 ±3 ±3 ±3 ±3±3 ±3 ±30 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5 ±4.5
0
10
20
30
40
50
60
70
80
Temperature (°C)

RH (%RH)
100 ±2
90 ±2
80 ±2
70 ±2
60 ±2
50 ±2
40 ±2
30 ±2
20 ±2
10 ±2
0 ±2
0

Figure 5 Typical tolerance of RH over T for SHT30.

Figure 6 Typical tolerance of RH over T for SHT31.

±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
10

±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2±2
±2 ±2 ±2
±2
20
30
40
50
Temperature (°C)

±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
60

±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
70

±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
80

SHT35
RH (%RH)
100
90
80
70
60
50
40
30
20
10
0

±2
±2
±2
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
0

±2
±2

±2
±2

±2
±2

±2
±2

±2
±2

±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
10

±1.5 ±1.5 ±1.5 ±1.5
±1.5 ±1.5 ±1.5 ±1.5
±1.5 ±1.5 ±1.5 ±1.5
±1.5 ±1.5 ±1.5 ±1.5
±1.5 ±1.5 ±1.5 ±1.5
±1.5 ±1.5 ±1.5 ±1.5
±1.5 ±1.5 ±1.5 ±1.5
±1.5 ±1.5 ±1.5 ±1.5
20
30
40
50
Temperature (°C)

±2
±2
±2
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
60

±2
±2
±2
±2
±2
±2
±1.5
±1.5
±1.5
±1.5
±1.5
70

±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
±2
80

Figure 7 Typical tolerance of RH over T for SHT35.

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Datasheet SHT3x-DIS

Temperature Sensor Performance Graphs
SHT30

SHT31

DT (°C)±1.5

DT (°C)±1.5

maximal tolerance

maximal tolerance

typical tolerance±1.0

typical tolerance

±1.0

±0.5

±0.5

±0.0

±0.0
-40

-20

0

20

40

60

80

100

120

-40

-20

0

20

Temperature (°C)

Figure 8 Temperature accuracy of the SHT30 sensor.

40

60

80

100

120

Temperature (°C)

Figure 9 Temperature accuracy of the SHT31 sensor.

SHT35
DT (°C)±1.5

maximal tolerance
typical tolerance
±1.0

±0.5

±0.0
-40

-20

0

20

40

60

80

100

120

Temperature (°C)

Figure 10 Temperature accuracy of the SHT35 sensor.

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Datasheet SHT3x-DIS

1.1

Recommended Operating Condition

The sensor shows best performance when operated within recommended normal temperature and humidity range of 5 °C
– 60 °C and 20 %RH – 80 %RH, respectively. Long-term exposure to conditions outside normal range, especially at highhumidity, may temporarily offset the RH signal (e.g. +3%RH after 60h kept at >80%RH). After returning into the normal
temperature and humidity range the sensor will slowly come back to calibration state by itself. Prolonged exposure to
extreme conditions may accelerate ageing. To ensure stable operation of the humidity sensor, the conditions described in
the document “SHTxx Assembly of SMD Packages”, section “Storage and Handling Instructions” regarding exposure tovolatile organic compounds have to be met. Please note as well that this does apply not only to transportation andmanufacturing, but also to operation of the SHT3x-DIS.

2

Specifications

2.1

Electrical Specifications

Parameter

SymbolSupply voltage
Power-up/down level

VDD
VPOR

Slew rate change of the
supply voltage

Condition

VDD,slew

Typ.

Max.

2.4
2.1

3.3
2.3

5.5
2.4

-

idle state(single shot mode)

Supply current

Min.

-

-

20

0.2

2.0

Heater power

PHeater

Voltage changes on the
VDD line between
VDD,min and VDD,max
V/ms should be slower thanthe maximum slew rate;
faster slew rates maylead to reset;
Current when sensor is
not performing aAmeasurement during
single shot mode

-

45

70

Current when sensor is
not performing a
A measurement during
periodic data acquisition
mode

Measuring

-

800

1500

A

2

-

A

2.1x VDD

mA

See also section 3.5

33mW

Depending on the
supply voltage

Average

IOH

V
V

idle state(periodic dataacquisition mode)
IDD

Alert Output driving
strength

Units Comments-

0.8x VDD 1.5x VDDHeater running

4.5-

Current consumption
while sensor ismeasuring
Current consumption(operation with one
measurement per
second at lowest
repeatability, single shot
mode)

Table 3 Electrical specifications, valid at 25°C.

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Datasheet SHT3x-DIS

2.2

Timing Specification for the Sensor System

Parameter

SymbolConditions

Min.

Typ.

Power-up timetPU

After hard reset,
VDD ≥ VPOR

-

0.5

1

ms

Soft reset timetSR

After soft reset.

-

0.5

1

ms

tRESETNtMEAS,lLow repeatability

1
-

2.5

4

µs
ms

tMEAS,mMedium repeatability

-

4.5

6

ms

tMEAS,hHigh repeatability

-

12.5

15

ms

Duration of reset pulse
Measurement duration

Max. Units Comments
Time between VDD reaching
VPOR and sensor entering idle
stateTime between ACK of soft
reset command and sensor
entering idle state
See section 3.6
The three repeatability modes
differ with respect tomeasurement duration, noiselevel and energy consumption.

Table 4 System timing specification, valid from -40 °C to 125 °C and 2.4 V to 5.5 V.

2.3

Absolute Minimum and Maximum Ratings

Stress levels beyond those listed in Table 5 may cause permanent damage to the device or affect the reliability of thesensor. These are stress ratings only and functional operation of the device at these conditions is not guaranteed.
Parameter

RatingUnits

Supply voltage VDD-0.3 to 6

V-0.3 to VDD+0.3

V

±100

mA

Operating temperature range
Storage temperature range-40 to 125-40 to 150°C°C

ESD HBM (human body model) 94kV

ESD CDM (charge device model) 10
750
Table 5 Minimum and maximum ratings; voltage values may only be applied for short time periods.

V

Max Voltage on pins (pin 1 (SDA); pin 2 (ADDR); pin 3 (ALERT); pin 4 (SCL); pin 6(nRESET))
Input current on any pin

9 According to ANSI/ESDA/JEDEC JS-001-2014; AEC-Q100-002.
10 According to ANSI/ESD S5.3.1-2009; AEC-Q100-011.

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Datasheet SHT3x-DIS

3

Pin Assignment

The SHT3x-DIS comes in a tiny 8-pin DFN package –see Table 6.
Pin

Name

Comments

1

SDA

2

ADDR

3

ALERT

Serial data; input / output
Address pin; input; connect to either
logic high or low, do not leave floating
Indicates alarm condition; output; mustbe left floating if unused

4
5

SCL
VDD

6

nRESETR

8

VSS

GroundVDD(5)

ALERT(3)

SCL(4)
SDA(1)8

ADDR(2)2

7

VSS(8) pad

3

6

4

5

die

RP

RP

R(7)

Figure 11 Typical application circuit. Please note that thepositioning of the pins does not reflect the position on thereal sensor. This is shown in Table 6.

Power Pins (VDD, VSS)

The electrical specifications of the SHT3x-DIS are
shown in Table 3. The power supply pins must be
decoupled with a 100 nF capacitor that shall be placed
as close to the sensor as possible – see Figure 11 for atypical application circuit.

3.2

nRESET(6)1

Table 6 SHT3x-DIS pin assignment (transparent top view).
Dashed lines are only visible if viewed from below. The die
pad is internally connected to VSS.

3.1

VDD

100nF

7

Serial clock; input / output
Supply voltage; input
Reset pin active low; input; if not used itis recommend to be left floating
No electrical function; to be connected
to VSS

Both SCL and SDA lines are open-drain I/Os with diodes
to VDD and VSS. They should be connected to external
pull-up resistors (please refer to Figure 11). A device on
the I2C bus must only drive a line to ground. The external
pull-up resistors (e.g. Rp=10 kΩ) are required to pull thesignal high. For dimensioning resistor sizes please takebus capacity and communication frequency into account(see for example Section 7.1 of NXPs I2C Manual for
more details11). It should be noted that pull-up resistors
may be included in I/O circuits of microcontrollers. It is
recommended to wire the sensor according to theapplication circuit as shown in Figure 11.

Serial Clock and Serial Data (SCL, SDA)SCL is used to synchronize the communication between
microcontroller and the sensor. The clock frequency canbe freely chosen between 0 to 1000 kHz. Commands
with clock stretching according to I2C Standard 11 aresupported.
The SDA pin is used to transfer data to and from thesensor. Communication with frequencies up to 400 kHz
must meet the I2C Fast Mode11 standard.
Communication frequencies up to 1 Mhz are supported
following the specifications given in Table 20.

3.3

Die Pad (center pad)

The die pad or center pad is visible from below andlocated in the center of the package. It is electricallyconnected to VSS. Hence electrical considerations do
not impose constraints on the wiring of the die pad.
However, due to mechanical reasons it is recommended
to solder the center pad to the PCB. For more
information on design-in, please refer to the document“SHTxx Design Guide”.

3.4

ADDR Pin

Through the appropriate wiring of the ADDR pin the I2C
address can be selected (see Table 7 for the respective
addresses). The ADDR pin can either be connected to
VDD or VSS, or it can be used as a selector pin. Thismeans that the address of the sensor can be changed
dynamically during operation by switching the level on
the ADDR pin. The only constraint is that the level has tostay constant starting from the I2C start condition until
the communication is finished. This allows to connect
more than two SHT3x-DIS onto the same bus. The
dynamical switching requires individual ADDR lines tothe sensors.

11 http://www.nxp.com/documents/user_manual/UM10204.pd f

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Datasheet SHT3x-DIS
Please note that the I2C address is represented throughthe 7 MSBs of the I2C read or write header. The LSB
switches between read or write header. The wiring forthe default address is shown in Table 7 and Figure 11.
The ADDR pin must not be left floating. Please note that
only the 7 MSBs of the I2C Read/Write header constitutethe I2C Address.
SHT3x-DIS

I2C Address in Hex.
representation

Condition

I2C address A

0x44 (default)

ADDR (pin 2)
connected to VSS

I2C address B

0x45

ADDR (pin 2)
connected to VDD

Table 7 I2C device addresses.

3.5

ALERT Pin

The alert pin may be used to connect to the interrupt pinof a microcontroller. The output of the pin depends onthe value of the RH/T reading relative to programmable
limits. Its function is explained in a separate applicationnote. If not used, this pin must be left floating. The pin
switches high, when alert conditions are met. The
maximum driving loads are listed in Table 3. Be awarethat self-heating might occur, depending on the amountof current that flows. Self-heating can be prevented if theAlert Pin is only used to switch a transistor.

3.6

nRESET Pin

The nReset pin may be used to generate a reset of thesensor. A minimum pulse duration of 1 µs is required toreliably trigger a reset of the sensor. Its function is
explained in more detail in section 4. If not used it isrecommended to leave the pin floating.

4

Operation and Communication

The SHT3x-DIS supports I2C fast mode (andfrequencies up to 1000 kHz). Clock stretching can be
enabled and disabled through the appropriate usercommand. For detailed information on the I2C protocol,
refer to NXP I2C-bus specification12.
All SHT3x-DIS commands and data are mapped to a 16bit address space. Additionally, data and commands areprotected with a CRC checksum. This increases
communication reliability. The 16 bits commands to thesensor already include a 3 bit CRC checksum. Data sentfrom and received by the sensor is always succeeded byan 8 bit CRC.

is followed by the correct checksum. In read direction itis left to the master to read and process the checksum.

4.1

Power-Up and Communication Start

The sensor starts powering-up after reaching the powerup threshold voltage VPOR specified in Table 3. Afterreaching this threshold voltage the sensor needs thetime tPU to enter idle state. Once the idle state is entered
it is ready to receive commands from the master(microcontroller).
Each transmission sequence begins with a START
condition (S) and ends with a STOP condition (P) as
described in the I2C-bus specification. The stop
condition is optional. Whenever the sensor is poweredup, but not performing a measurement orcommunicating, it automatically enters idle state forenergy saving. This idle state cannot be controlled by the
user.

4.2

Starting a Measurement

A measurement communication sequence consists of a
START condition, the I2C write header (7-bit I2C device
address plus 0 as the write bit) and a 16-bit
measurement command. The proper reception of eachbyte is indicated by the sensor. It pulls the SDA pin low(ACK bit) after the falling edge of the 8th SCL clock toindicate the reception. A complete measurement cycle isdepicted in Table 8.
With the acknowledgement of the measurement
command, the SHT3x-DIS starts measuring humidity
and temperature.

4.3

Measurement Commands for Single Shot
Data Acquisition ModeIn this mode one issued measurement command
triggers the acquisition of one data pair. Each data pairconsists of one 16 bit temperature and one 16 bit
humidity value (in this order). During transmission eachdata value is always followed by a CRC checksum, seesection 4.4.
In single shot mode different measurement commands
can be selected. The 16 bit commands are shown in
Table 8. They differ with respect to repeatability (low,medium and high) and clock stretching (enabled or
disabled).
The repeatability setting influences the measurement
duration and thus the overall energy consumption of thesensor. This is explained in section 2.

In write direction it is mandatory to transmit thechecksum, since the SHT3x-DIS only accepts data if it

12 http://www.nxp.com/documents/user_manual/UM10204.pd f

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Datasheet SHT3x-DIS
Condition
Repeatability

Hex. codeClockstretching

MSB

High
Medium06
enabled

0x2C

Low
High
Medium

LSB
0D
10
00

disabled

0x24

0B

Low
16
e.g. 0x2C06: high repeatability measurement with clock
stretching enabled

In case the user needs humidity and temperature data
but does not want to process CRC data, it isrecommended to read the two temperature bytes of datawith the CRC byte (without processing the CRC data);
after having read the two humidity bytes, the readtransfer can be aborted with a with a NACK.

No Clock Stretching
When a command without clock stretching has been
issued, the sensor responds to a read header with a not
acknowledge (NACK), if no data is present.

Clock Stretching
When a command with clock stretching has been issued,
the sensor responds to a read header with an ACK andsubsequently pulls down the SCL line. The SCL line ispulled down until the measurement is complete. As soon
as the measurement is complete, the sensor releases
the SCL line and sends the measurement results.

4.5

Measurement Commands for Periodic
Data Acquisition ModeIn this mode one issued measurement command yields
a stream of data pairs. Each data pair consists of one 16
bit temperature and one 16 bit humidity value (in thisorder).
Table 8 Measurement commands in single shot mode (Clear
blocks are controlled by the microcontroller, grey blocks by
the sensor).

4.4

Readout of Measurement Results forSingle Shot Mode

After the sensor has completed the measurement, themaster can read the measurement results (pair of RH&T) by sending a START condition followed by an I2C
read header. The sensor will acknowledge the receptionof the read header and send two bytes of data
(temperature) followed by one byte CRC checksum andanother two bytes of data (relative humidity) followed by
one byte CRC checksum. Each byte must be
acknowledged by the microcontroller with an ACK
condition for the sensor to continue sending data. If thesensor does not receive an ACK from the master after
any byte of data, it will not continue sending data.

In periodic mode different measurement commands canbe selected. The corresponding 16 bit commands areshown in Table 9. They differ with respect to repeatability(low, medium and high) and data acquisition frequency(0.5, 1, 2, 4 & 10 measurements per second, mps). Clockstretching cannot be selected in this mode.
The data acquisition frequency and the repeatability
setting influences the measurement duration and thecurrent consumption of the sensor. This is explained in
section 2 of this datasheet.
If a measurement command is issued, while the sensor
is busy with a measurement (measurement durations
see Table 4), it is recommended to issue a breakcommand first (see section 4.8). Upon reception of the
break command the sensor will finish the ongoingmeasurement and enter the single shot mode.

The sensor will send the temperature value first and thenthe relative humidity value. After having received thechecksum for the humidity value a NACK and stop
condition should be sent (see Table 8).
The I2C master can abort the read transfer with a NACK
condition after any data byte if it is not interested insubsequent data, e.g. the CRC byte or the second
measurement result, in order to save time.
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Datasheet SHT3x-DIS
Condition
Repeatability
mps

Hex. code
MSB
LSB

High

32

Medium

0.5

0x20

24

Low
High

2F
30

Medium

1

0x21

Low

2D
36
20

2

0x22

Low

2B

High
Medium

34
22

4

0x23

The ART feature can also be evaluated using the
Evaluation Kit EK-H5 from Sensirion.
Periodic Measurement withART

0x2B32

37
21

S

2A

Table 11 Command for a periodic data acquisition with

10

0x27

5

6

I2C Address

7

8

9

W

1

2

3

4

5

6

7

Command MSB

8

9

4

5

6

7

8

9

W

I2C write header

1

2

3

4

5

6

7

Command MSB

89

10 11 12 13 14 15 16 17 18

Command LSB

ACK

3

ACK

2

I2C Address

ACK116-bit command

the ART feature (Clear blocks are controlled by the
microcontroller, grey blocks by the sensor).

10 11 12 13 14 15 16 17 18

Command LSB

ACK

4

ACK

3

I2C write header

16-bit command

Table 9 Measurement commands for periodic data acquisitionmode (Clear blocks are controlled by the microcontroller, grey
blocks by the sensor). N.B.: At the highest mps setting selfheating of the sensor might occur.

4.6

Hex Code

29

ACK

S

CommandLow

e.g. 0x2130: 1 high repeatability mps - measurement per
second2

The ART (accelerated response time) feature can be
activated by issuing the command in Table 11. Afterissuing the ART command the sensor will start acquiring
data with a frequency of 4Hz.

High
MediumLow

1

ART Command

The ART command is structurally similar to any othercommand in Table 9. Hence section 4.5 applies forstarting a measurement, section 4.6 for reading out dataand section 4.8 for stopping the periodic data acquisition.

26

High
Medium

4.7

Readout of Measurement Results for
Periodic Mode

Transmission of the measurement data can be initiatedthrough the fetch data command shown in Table 10. If
no measurement data is present the I2C read header is
responded with a NACK (Bit 9 in Table 10) and thecommunication stops. After the read out command fetch
data has been issued, the data memory is cleared, i.e.
no measurement data is present.
Command

Hex code

Fetch Data0x E0 00

4.8

Break command / Stop Periodic Data
Acquisition Mode

The periodic data acquisition mode can be stopped using
the break command shown in Table 12. It is
recommended to stop the periodic data acquisition prior
to sending another command (except Fetch Data
command) using the break command. Upon reception of
the break command the sensor enters the single shotmode, after finishing the ongoing measurement. Thiscan take up to 15 ms, depending on the selected
repeatability.
CommandHex Code

Break0x3093

Table 12 Break command (Clear blocks are controlled by
the microcontroller, grey blocks by the sensor).

4.9

Reset

A system reset of the SHT3x-DIS can be generated
externally by issuing a command (soft reset) or by
sending a pulse to the dedicated reset pin (nReset pin).
Additionally, a system reset is generated internallyduring power-up. During the reset procedure the sensor
will not process commands.
Table 10 Fetch Data command (Clear blocks are controlled
by the microcontroller, grey blocks by the sensor).

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In order to achieve a full reset of the sensor without
removing the power supply, it is recommended to use thenRESET pin of the SHT3x-DIS.

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Datasheet SHT3x-DIS

Interface Reset
Code

Address byte
Second byte
Reset command using thegeneral call address

0x00
0x06

1

2

3

4

5

6

7

8

S General Call Address
General Call 1st byte

The SHT3x-DIS provides a soft reset mechanism thatforces the system into a well-defined state without
removing the power supply. When the system is in idle
state the soft reset command can be sent to the SHT3xDIS. This triggers the sensor to reset its system
controller and reloads calibration data from the memory.
In order to start the soft reset procedure the commandas shown in Table 13 should be sent.
It is worth noting that the sensor reloads calibration dataprior to every measurement by default.
CommandHex Code

Soft Reset

0x30A20x0006
9

1

2

3

4

5

6

7

Reset Command

8

9

ACK

Soft Reset / Re-Initialization

Command

ACK

If communication with the device is lost, the following
signal sequence will reset the serial interface: Whileleaving SDA high, toggle SCL nine or more times. This
must be followed by a Transmission Start sequence
preceding the next command. This sequence resets theinterface only. The status register preserves its content.

General Call 2nd byte

Table 14 Reset through the general call address (Clear
blocks are controlled by the microcontroller, grey blocks by
the sensor).

Hard Reset
A hard reset is achieved by switching the supply voltage
to the VDD Pin off and then on again. In order to prevent
powering the sensor over the ESD diodes, the voltage topins 1 (SDA), 4 (SCL) and 2 (ADDR) also needs to be
removed.

4.10 Heater
The heater can be switched on and off by command, seetable below. The status is listed in the status register.
After a reset the heater is disabled (default condition).

Table 13 Soft reset command (Clear blocks are controlled
by the microcontroller, grey blocks by the sensor).

Heater Enable
Heater Disabled

Reset through General Call
Additionally, a reset of the sensor can also be generatedusing the “general call” mode according to I2C-bus
specification12. This generates a reset which isfunctionally identical to using the nReset pin. It is
important to understand that a reset generated in thisway is not device specific. All devices on the same I2C
bus that support the general call mode will perform areset. Additionally, this command only works when thesensor is able to process I2C commands. The
appropriate command consists of two bytes and isshown in Table 14.

Reset through the nReset Pin
Pulling the nReset pin low (see Table 6) generates areset similar to a hard reset. The nReset pin is internallyconnected to VDD through a pull-up resistor and hence
active low. The nReset pin has to be pulled low for aminimum of 1 µs to generate a reset of the sensor.

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CommandHex Code
MSB
LSB
0x30

6D
66

Table 15 Heater command (Clear blocks are controlled by
the microcontroller, grey blocks by the sensor).

4.11 Status Register
The status register contains information on theoperational status of the heater, the alert mode and on
the execution status of the last command and the last
write sequence. The command to read out the status
register is shown in Table 16 whereas a description of
the content can be found in Table 17.

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Datasheet SHT3x-DIS
Command

Hex code

CommandHex Code

Read Out of status register

0xF32D

Clear status register0x 30 41

Table 18 Command to clear the status register (Clear
blocks are controlled by the microcontroller, grey blocks by
the sensor).

Table 16 Command to read out the status register (Clear
blocks are controlled by the microcontroller, grey blocks by
the sensor).

Bit

Field description

15

Alert pending status'0': no pending alerts'1': at least one pending alert
Reserved
Heater status‘0’ : Heater OFF‘1’ : Heater ON
Reserved
RH tracking alert‘0’ : no alert‘1’ . alert
T tracking alert‘0’ : no alert‘1’ . alert

14
13
12
11
10

9:5
4

Reserved

System reset detected

Default
value
‘1’

3:2
1

0

Value

Name

CRC-8

Width

8 bit

Protected data
Polynomial

read and/or write data
0x31 (x 8 + x 5 + x 4 + 1)‘0’‘0Initialization

0xFF

Reflect input
Reflect output

False
False

‘0’

Final XOR

0x00

ExamplesCRC (0xBEEF) = 0x92

‘0’
‘0’

‘xxxxx’

Table 19 I2C CRC properties.

‘1’

4.13 Conversion of Signal Output

‘00’
‘0’

Measurement data is always transferred as 16-bit values(unsigned integer). These values are already linearized
and compensated for temperature and supply voltage
effects. Converting those raw values into a physicalscale can be achieved using the following formulas.
Relative humidity conversion formula (result in %RH):
RH  100 

‘0’

S RH
2 16  1

Temperature conversion formula (result in °C & °F):S
T C    45  175  16 T
2 1S
T F    49  315  16 T
2 1Table 17 Description of the status register.

Clear Status RegisterAll flags (Bit 15, 11, 10, 4) in the status register can becleared (set to zero) by sending the command shown in
Table 18.

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The 8-bit CRC checksum transmitted after each data
word is generated by a CRC algorithm. Its properties are
displayed in Table 19. The CRC covers the contents ofthe two previously transmitted data bytes. To calculate
the checksum only these two previously transmitted databytes are used.
Property'0': no reset detected since last ‘clear
status register’ command'1': reset detected (hard reset, soft reset
command or supply fail)Reserved
Command status'0': last command executed successfully'1': last command not processed. It waseither invalid, failed the integrated
command checksum
Write data checksum status'0': checksum of last write transfer wascorrect'1': checksum of last write transfer failed

4.12 Checksum Calculation

SRH and ST denote the raw sensor output for humidity
and temperature, respectively. The formulas work only
correctly when SRH and ST are used in decimal
representation.

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4.14 Communication Timing
Parameter
SCL clock frequency

SymbolConditions

Min.

Typ.

Max.

Units

0

-

1000

kHz

0.24

-

-

µs

fSCL

Hold time (repeated) START
condition

tHD;STALOW period of the SCL
clock

tLOW

0.65

-

-

µs

HIGH period of the SCL
clock

tHIGH

0.26

-

-

µs

SDA hold time

tHD;DAT

0

-

250

ns

Transmitting data

0

-

-

ns

Receiving data

SDA set-up time
SCL/SDA rise time

tSU;DAT
tR

100
-

-

300

ns
ns

SCL/SDA fall time

tF

-

-

300

ns

tVD;DAT

-

-

0.9

µs

tSU;STA

0.6

-

-

µs

tSU;STO

0.6

-

-

µs

CB

-

-

400

pF

Low level input voltage

VIL

-0.5

-

0.3xVDD

V

High level input voltage
Low level output voltage

VIH
VOL

0.7xVDD
-

-

1xVDD
0.66

V
V

SDA valid timeSet-up time for a repeated
START condition
Set-up time for STOP
condition
Capacitive load on bus line

After this period, the firstclock pulse is generated

Comments

3 mA sink current

Table 20 Communication timing specifications for I2C fm (fast mode), specifications are at 25°C and typical VDD. The numbers above
are values according to the I2C Specification (UM10204, Rev. 6, April 4, 2014).
1/fSCL

tHIGH

tR

tLOW

tF
70%

SCL
tSU;DAT30%
tHD;DATDATA IN

70%

SDA

30%
tVD;DATtF

DATA OUT

tR
70%

SDA

30%

Figure 12 Timing diagram for digital input/output pads. SDA directions are seen from the sensor. Bold SDA lines arecontrolled by the sensor, plain SDA lines are controlled by the micro-controller. Note that SDA valid read time is triggered
by falling edge of preceding toggle.

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Datasheet SHT3x-DIS

5

Packaging

SHT3x-DIS sensors are provided in an open-cavity DFN
package. DFN stands for dual flat no leads. The humidity
sensor opening is centered on the top side of the
package.
The sensor chip is made of silicon and is mounted to alead frame. The latter is made of Cu plated with
Ni/Pd/Au. Chip and lead frame are overmolded by anepoxy-based mold compound leaving the central die pad
and I/O pins exposed for mechanical and electricalconnection. Please note that the side walls of the sensor
are diced and therefore these diced lead frame surfaces
are not covered with the respective plating.
The package (except for the humidity sensor opening)
follows JEDEC publication 95, design registration 4.20,
small scale plastic quad and dual inline, square andrectangular, No-LEAD packages (with optional thermalenhancements) small scale (QFN/SON), Issue D.01,
September 2009.

The top line consist of the pin-1 indicator which is locatedin the top left corner and the product name. The small
letter x stands for the accuracy class.
The bottom line consists of 6 letters. The first two digits
XY (=DI) describe the output mode. The third letter (A)represents the manufacturing year (4 = 2014, 5 = 2015,etc). The last three digits (BCD) represent analphanumeric tracking code. That code can be decodedby Sensirion only and allows for tracking on batch level
through production, calibration and testing – and will be
provided upon justified request.
If viewed from below pin 1 is indicated by triangularshaped cut in the otherwise rectangular die pad. The
dimensions of the triangular cut are shown in Figure 14
through the labels T1 & T2.

SHT 3 x

SHT3x-DIS has a Moisture Sensitivity Level (MSL) of 1,
according to IPC/JEDEC J-STD-020. At the same time,
it is recommended to further process the sensors within
1 year after date of delivery.

5.1

XYABCD

Traceability

All SHT3x-DIS sensors are laser marked for easy
identification and traceability. The marking on the sensor
top side consists of a pin-1 indicator and two lines of text.

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Figure 13 Top view of the SHT3x-DIS illustrating the laser
marking.

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Datasheet SHT3x-DIS

5.2

Package Outline

Figure 14 Dimensional drawing of SHT3x-DIS sensor package

Parameter

Symbol

Min

Nom.

Max

Units Comments

Package height

A

0.8

0.9

1

mm

Leadframe height

A3

-

0.2

-

mm

Pad width
Package width

b
D

0.2
2.4

0.25
2.5

0.3
2.6

mm
mm

Center pad length

D2

1

1.1

1.2

mm

Package length

E

2.4

2.5

2.6

mm

Center pad width
Pad pitch

E2
e

1.7
-

1.8
0.5

1.9

mm
mm

Pad length

L

0.3

0.35

0.4

mm

S

-

-

1.5

mm

Only as guidance. This value includes all tolerances,including displacement tolerances. Typically the opening
will be smaller.

T1xT2

-

0.3x45°-mmindicates the position of pin 1

Max cavity
Center pad marking
Table 21 Package outline.

5.3

Land PatternFigure 15 shows the land pattern. The land pattern isunderstood to be the open metal areas on the PCB, onto
which the DFN pads are soldered.
The solder mask is understood to be the insulating layer
on top of the PCB covering the copper traces. It is
recommended to design the solder pads as a NonSolder Mask Defined (NSMD) type. For NSMD pads, thesolder mask opening should provide a 60 μm to 75 μm
design clearance between any copper pad and solder
mask. As the pad pitch is only 0.5 mm we recommend tohave one solder mask opening for all 4 I/O pads on one
side.

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For solder paste printing it is recommended to use alaser-cut, stainless steel stencil with electro-polishedtrapezoidal walls and with 0.1 or 0.125 mm stencil
thickness. The length of the stencil apertures for the I/O
pads should be the same as the PCB pads. However,the position of the stencil apertures should have an offset
of 0.1 mm away from the center of the package. The die
pad aperture should cover about 70 – 90 % of the die
pad area –thus it should have a size of about 0.9 mm x
1.6 mm.
For information on the soldering process and further
recommendation on the assembly process please
consult
theApplication
Note
HT_AN_SHTxx_Assembly_of_SMD_Packages , which
can be found on the Sensirion webpage.

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Datasheet SHT3x-DIS

land patternstencil aperture

sensor outline

0.25

1.6

0.5

0.4

0.45

0.5

0.375

1.7

0.5

0.375

0.5

0.25

0.5

0.5

0.3x45°

0.3

0.2
0.55

1

0.55

0.75

0.55

0.9

0.8

Figure 15 Recommended metal land pattern (left) and stencil apertures (right) for the SHT3x-DIS. The dashed lines represent theouter dimension of the DFN package. The PCB pads (left) and stencil apertures (right) are indicated through the shaded areas.

6

Shipping Package
Ø1.5 +.1 /-0.0
4.00
2.00 ±.05 SEE Note 2

Ø1.00 MIN
1.75 ±.1

4.00 SEE Note 10.30 ±.05

A

5.50 ±.05
SEE NOTE 2

R 0.2 MAX.
B0
B

12.0 +0.3/-0.1
A

R 0.25 TYP.

K0
A0

SECTION A - A

A0 = 2.75
B0 = 2.75
K0 = 1.20
TOLERANCES - UNLESSNOTED 1PL ±.2 2PL ±.10

NOTES:
1. 10 SPROCKET HOLE PITCH CUMULATIVE TOLERANCE ±0.2
2. POCKET POSITION RELATIVE TO SPROCKET HOLE MEASURED
AS TRUE POSITION OF POCKET, NOT POCKET HOLE
3. A0 AND B0 ARE CALCULATED ON A PLANE AT A DISTANCE "R"ABOVE THE BOTTOM OF THE POCKETDETAIL B

Figure 16 Technical drawing of the packaging tape with sensor orientation in tape. Header tape is to the right and trailer tape to theleft on this drawing. Dimensions are given in millimeters.

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Datasheet SHT3x-DIS

7“SHT3x shipping package” that shows the details about
the shipping package is available upon request.

Quality

Qualification of the SHT3x-DIS is performed based on
the AEC Q 100 qualification test method.

Name

Quantity

Order Number

SHT30-DIS-B2.5kS
SHT30-DIS-B10kS

2500
10000

1-101400-01
1-101173-01

The device is fully RoHS and WEEE compliant, e.g. freeof Pb, Cd, and Hg.

SHT31-DIS-B2.5kS

2500

1-101386-01

SHT31-DIS-B10kS

10000

1-101147-01

8

SHT35-DIS-B2.5kS
SHT35-DIS-B10kS

2500
10000

1-101388-01
1-101479-01

7.1

Material Contents

Ordering Information

The SHT3x-DIS can be ordered in tape and reelpackaging with different sizes, see Table 22. The reels
are sealed into antistatic ESD bags. The document

9

Table 22 SHT3x-DIS ordering options.

Further Information

For more in-depth information on the SHT3x-DIS and its application please consult the following documents:
Document Name

Description

SourceSHT3x Shipping Package

Information on Tape, Reel and shipping bags
(technical drawing and dimensions)

Available upon request
Available for download at the Sensirion
humidity sensors download center:

SHTxx Assembly of SMD
Packages

Assembly Guide (Soldering Instructions)

SHTxx Design Guide

Design guidelines for designing SHTxx humidity
sensors into applications

SHTxx Handling Instructions

Available for download at the Sensirion
Guidelines for proper handling of SHTxx humidity
humidity sensors download center:sensors
www.sensirion.com/humidity-download

Sensirion Humidity Sensor
Specification Statement

Definition of sensor specifications.

www.sensirion.com/humidity-download
Available for download at the Sensirion
humidity sensors download center:www.sensirion.com/humidity-download

Available for download at the Sensirion
humidity sensors download center:www.sensirion.com/humidity-download

Table 23 Documents containing further information relevant for the SHT3x-DIS.

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Datasheet SHT3x-DIS

Revision History
Date

VersionOctober 2015

1

June 20162

August 2016www.sensirion.com

3

Page(s)Changes-

2-4Specifications for SHT35 added

6

ESD specifications updated

7

Table 6 “Comments” section updated

7

Figure 11 updated according to Table 6

11

Updated information about data memory to: “After the read out command “fetchdata” has been issued, the data memory is reset, i.e. no measurement data ispresent.

17

Ordering information in Table 22 updated

6

Updated Table 3

7Updated Table 4

7Updated information on ESD testing norm

8

Updated Table 6

8

Figure 11 and Table 6 updated

4

Figure 7 updated

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Datasheet SHT3x-DIS

Important Notices
Warning, Personal Injury
Do not use this product as safety or emergency stop devices orin any other application where failure of the product could resultin personal injury. Do not use this product for applications otherthan its intended and authorized use. Before installing, handling,using or servicing this product, please consult the data sheet
and application notes. Failure to comply with these instructions
could result in death or serious injury.
If the Buyer shall purchase or use SENSIRION products for any
unintended or unauthorized application, Buyer shall defend,
indemnify and hold harmless SENSIRION and its officers,
employees, subsidiaries, affiliates and distributors against all claims,
costs, damages and expenses, and reasonable attorney fees arisingout of, directly or indirectly, any claim of personal injury or deathassociated with such unintended or unauthorized use, even if
SENSIRION shall be allegedly negligent with respect to the design or
the manufacture of the product.
ESD Precautions
The inherent design of this component causes it to be sensitiv e toelectrostatic discharge (ESD). To prevent ESD-induced damage
and/or degradation, take customary and statutory ESD precautions
when handling this product.
See application note “ESD, Latchup and EMC” for more information.
Warranty
SENSIRION warrants solely to the original purchaser of this productfor a period of 12 months (one year) from the date of delivery that thisproduct shall be of the quality, material and workmanship defined in
SENSIRION’s published specifications of the product. Within such
period, if proven to be defective, SENSIRION shall repair and/or
replace this product, in SENSIRION’s discretion, free of charge to the
Buyer, provided that:
notice in writing describing the defects shall be given to
SENSIRION within fourteen (14) days after their appearance;such defects shall be found, to SENSIRION’s reasonablesatisfaction, to have arisen from SENSIRION’s faulty design,material, or workmanship;the defective product shall be returned to SENSIRION’s
factory at the Buyer’s expense; and
the warranty period for any repaired or replaced product shallbe limited to the unexpired portion of the original period.
This warranty does not apply to any equipment which has not been
installed and used within the specifications recommended by
SENSIRION for the intended and proper use of the equipment.
EXCEPT FOR THE WARRANTIES EXPRESSLY SET FORTHHEREIN, SENSIRION MAKES NO WARRANTIES, EITHER
EXPRESS OR IMPLIED, WITH RESPECT TO THE PRODUCT. ANY
AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION,WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE, ARE EXPRESSLY EXCLUDED AND
DECLINED.
SENSIRION is only liable for defects of this product arising under theconditions of operation provided for in the data sheet and proper useof the goods. SENSIRION explicitly disclaims all warranties, express
or implied, for any period during which the goods are operated orstored not in accordance with the technical specifications.
SENSIRION does not assume any liability arising out of any
application or use of any product or circuit and specifically disclaims
any and all liability, including without limitation consequential orincidental damages. All operating parameters, including without
limitation recommended parameters, must be validated for eachcustomer’s applications by customer’s technical experts.
Recommended parameters can and do vary in different applications.
SENSIRION reserves the right, without further notice, (i) to change
the product specifications and/or the information in this document and(ii) to improve reliability, functions and design of this product.
Copyright © 2016, by SENSIRION.
CMOSens® is a trademark of Sensirion
All rights reserved.

Headquarters and Subsidiaries

SENSIRION AG
Laubisruetistr. 50
CH-8712 Staefa ZH
Switzerland

Sensirion Inc. USA
phone: +1 805 409 4900
info_us@sensirion.com
www.sensirion.com

Sensirion Korea Co. Ltd.
phone: +82 31 337 7700~3
info-kr@sensirion.com
www.sensirion.co.kr

phone: +41 44 306 40 00
fax:+41 44 306 40 30
info@sensirion.com
www.sensirion.com

Sensirion Japan Co. Ltd.
phone: +81 3 3444 4940
info-jp@sensirion.com
www.sensirion.co.jp

Sensirion China Co. Ltd.
phone: +86 755 8252 1501
info-cn@sensirion.com
http://www.sensirion.com.cn/

Sensirion AG (Germany)
phone: +41 44 927 11 66

To find your local representative, please visit www.sensirion.com/contact

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