Datasheet SHT3xA-DIS
Automotive Grade Humidity and Temperature Sensor
Automotive grade, AEC-Q100 qualified
Fully calibrated, linearized, and temperature
compensated 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
SHT35A
Very fast start-up and measurement time
Product Summary
SHT3xA-DIS is the next generation of Sensirion’s
automotive grade 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 SHT3xA-DIS has increased intelligence,
reliability and improved accuracy specifications
compared to its predecessor. Its functionality includes
enhanced signal processing, two distinctive and user
selectable I2C addresses and communication speeds of
up to 1 MHz. The DFN package has a footprint of 2.5 x
2.5 mm2 while keeping a height of 0.9 mm. This allows
for integration of the SHT3xA-DIS into a great variety of
applications. Additionally, the wide supply voltage range
of 2.4 V to 5.5 V guarantees compatibility with a wide
range of applications. Its design and test coverage is
specifically optimized for the high quality standards of the
automotive industry.
Benefits of Sensirion’s CMOSens® Technology
9
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
Further Information ............................................ 19
nRESET
RH Sensor T Sensor
ADC
ADC
Sensor Performance.............................................2
2
Specifications .......................................................6
3
Pin Assignment ....................................................8
4
Operation and Communication .............................9
5
Packaging...........................................................15
6
Shipping Package ..............................................17
7
Quality ................................................................18
Power on
Reset
VSS
Calibration
Memory
Content
1
VDD
Data processing
& Linearization
Digital Interface
ADDR
SDA SCL
RESET
Alert Logic
Alert
Figure 1 Functional block diagram of the SHT3xA-DIS. The
sensor signals for humidity and temperature are factory
calibrated, linearized and compensated for temperature
and supply voltage dependencies.
8
Ordering Information...........................................18
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Datasheet SHT3xA-DIS
1
Sensor Performance
Humidity Sensor Specification
Parameter
SHT30A Accuracy tolerance1
SHT31A Accuracy tolerance1
SHT35A Accuracy tolerance1
Repeatability2
Resolution
Hysteresis
Specified range3
Response time5
Long-term drift
Condition
Value
Units
Typ.
Max.
Typ.
Max.
Typ.
Max.
Low, typ.
Medium, typ.
High, typ.
Typ.
at 25°C
extended4
63%
Typ.7
3
Figure 2
2
Figure 3
±1.5
Figure 4
0.21
0.15
0.08
0.01
0.8
0 to 100
86
2
s
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 to
volatile organic compounds have to be met. Please note as well that this does apply not only to transportation and
manufacturing, but also to operation of the SHT3xA-DIS.
2
2.1
Specifications
Electrical Specifications
Parameter
Supply voltage
Power-up/down level
Slew rate change of the
supply voltage
Symbol
Condition
VDD
VPOR
VDD,slew
idle state
(single shot mode)
T= 25°C
idle state
(single shot mode)
T= 125°C
Supply current
IDD
Heater power
Max.
2.4
2.1
3.3
2.3
5.5
2.4
-
-
20
-
0.2
2.0
Units Comments
V
V
Voltage changes on the
VDD line between
VDD,min and VDD,max
V/ms should be slower than
the maximum slew rate;
faster slew rates may
lead to reset;
A
-
-
6.0
Current when sensor is
not performing a
measurement during
single shot mode
Current when sensor is
not performing a
A measurement during
periodic data acquisition
mode
Current consumption
A while sensor is
measuring
Current consumption
(operation with one
measurement per
A
second at lowest
repeatability, single shot
mode)
-
45
-
Measuring
-
600
1500
1.7
-
-
1.5x VDD
-
mA
See also section 3.5
4.5
-
33
mW
Depending on the
supply voltage
IOH
PHeater
Typ.
idle state
(periodic data
acquisition mode)
Average
Alert Output driving
strength
Min.
Heater running
-
Table 3 Electrical specifications, typical values are valid for T=25°C, min. & max. values for T=-40°C … 125°C.
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Datasheet SHT3xA-DIS
2.2
Timing Specification for the Sensor System
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Power-up time
tPU
After hard reset,
VDD ≥ VPOR
-
0.5
1
Soft reset time
tSR
After soft reset.
-
0.5
1
tRESETN
tMEAS,l
tMEAS,m
Low repeatability
Medium repeatability
1
-
2.5
4.5
4
6
tMEAS,h
High repeatability
-
12.5
15
Duration of reset pulse
Measurement duration
Units Comments
Time between VDD reaching
ms VPOR and sensor entering idle
state
Time between ACK of soft
ms reset command and sensor
entering idle state
µs See section 3.6
ms The three repeatability modes
ms differ with respect to
measurement duration, noise
ms level 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 the
sensor. These are stress ratings only and functional operation of the device at these conditions is not guaranteed. Ratings
are only tested each at a time.
Parameter
Rating
Supply voltage VDD
-0.3 to 6
Max Voltage on pins (pin 1 (SDA); pin 2 (ADDR); pin 3 (ALERT); pin 4 (SCL); pin 6
-0.3 to VDD+0.3
(nRESET))
Input current on any pin
±100
Operating temperature range
-40 to 125
Storage temperature range
-40 to 150
9
ESD HBM (human body model)
4
ESD CDM (charge device model)10
750
Table 5 Minimum and maximum ratings; voltages may only be applied for short time periods.
9
Units
V
V
mA
°C
°C
kV
V
According to ANSI/ESDA/JEDEC JS-001-2014; AEC-Q100-002.
According to ANSI/ESD S5.3.1-2009; AEC-Q100-011.
10
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Datasheet SHT3xA-DIS
3
Communication frequencies up to 1 Mhz are supported
following the specifications given in Table 20.
Pin Assignment
The SHT3xA-DIS comes in a tiny 8-pin DFN package –
see Table 6.
Name
Comments
1
SDA
2
ADDR
3
ALERT
4
5
SCL
VDD
6
nRESET
7
R
8
VSS
Serial data; input / output
Address pin; input; connect to either
logic high or low, do not leave floating
Indicates alarm condition; output; must
be left floating if unused
Serial clock; input / output
Supply voltage; input
Reset pin active low; input; if not used it
is recommended to be left floating; can
be connected to VDD with a series
resistor of R ≥2 kΩ
No electrical function; to be connected
to VSS
Ground
1
8
2
7
3
6
4
5
VDD
nRESET(6)
VDD(5)
ALERT(3)
SCL(4)
ADDR(2)
SDA(1)
die
VSS(8) pad
100nF
Pin
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 the
signal high. For dimensioning resistor sizes please take
bus 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 the
application circuit as shown in Figure 11.
RP
RP
R(7)
Figure 11 Typical application circuit. Please note that the
positioning of the pins does not reflect the position on the
real sensor. This is shown in Table 6.
Table 6 SHT3xA-DIS pin assignment (transparent top view).
Dashed lines are only visible if viewed from below. The die
pad is internally connected to VSS.
3.3
Die Pad (center pad)
The electrical specifications of the SHT3xA-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 a
typical application circuit.
The die pad or center pad is visible from below and
located in the center of the package. It is electrically
connected 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 STSxx Design Guide”.
3.2
3.4
3.1
Power Pins (VDD, VSS)
Serial Clock and Serial Data (SCL, SDA)
SCL is used to synchronize the communication between
microcontroller and the sensor. The clock frequency can
be freely chosen between 0 to 1000 kHz. Commands
with clock stretching according to I2C Standard11 are
supported.
The SDA pin is used to transfer data to and from the
sensor. Communication with frequencies up to 400 kHz
must meet the I2C Fast Mode11 standard.
11
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
logic high or logic low. 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 to stay constant starting from the I2C start
condition until the communication is finished. This allows
to connect more than two SHT3xA-DIS onto the same
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Datasheet SHT3xA-DIS
bus. The dynamical switching requires individual ADDR
lines to the sensors.
Please note that the I2C address is represented through
the 7 MSBs of the I2C read or write header. The LSB
switches between read or write header. The wiring for
the 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 constitute
the I2C Address.
SHT3xA-DIS
I2C Address in Hex.
representation
I2C address A
0x44 (default)
I2C address B
0x45
Condition
ADDR (pin 2)
connected to logic
low
ADDR (pin 2)
connected to logic
high
Table 7 I2C device addresses.
3.5
ALERT Pin
The alert pin may be used to connect to the interrupt pin
of a microcontroller. The output of the pin depends on
the value of the RH/T reading relative to programmable
limits. Its function is explained in a separate application
note. 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 aware
that self-heating might occur, depending on the amount
of current that flows. Self-heating can be prevented if the
Alert Pin is only used to switch a transistor.
3.6
nRESET Pin
The nReset pin may be used to generate a reset of the
sensor. A minimum pulse duration of 1 µs is required to
reliably trigger a reset of the sensor. Its function is
explained in more detail in section 4. If not used it is
recommended to leave the pin floating or to connect it to
VDD with a series resistor of R ≥2 kΩ. However, the
nRESET pin is internally connected to VDD with a pull
up resistor of R = 50 kΩ (typ.).
4
Operation and Communication
The SHT3xA-DIS supports I2C fast mode (and
frequencies up to 1000 kHz). Clock stretching can be
enabled and disabled through the appropriate user
command. For detailed information on the I2C protocol,
refer to NXP I2C-bus specification12.
After sending a command to the sensor a minimal
waiting time of 1ms is needed before another
command can be received by the sensor
12
All SHT3xA-DIS commands and data are mapped to a
16-bit address space. Additionally, data and commands
are protected with a CRC checksum. This increases
communication reliability. The 16 bits commands to the
sensor already include a 3 bit CRC checksum. Data sent
from and received by the sensor is always succeeded by
an 8 bit CRC.
In write direction it is mandatory to transmit the
checksum, since the SHT3xA-DIS only accepts data if it
is followed by the correct checksum. In read direction it
is 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. After
reaching this threshold voltage the sensor needs the
time 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. Whenever the
sensor is powered up, but not performing a
measurement or communicating, it automatically enters
idle state for energy 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 each
byte is indicated by the sensor. It pulls the SDA pin low
(ACK bit) after the falling edge of the 8th SCL clock to
indicate the reception. A complete measurement cycle is
depicted in Table 8.
With the acknowledgement of the measurement
command, the SHT3xA-DIS starts measuring humidity
and temperature.
4.3
Measurement Commands for Single Shot
Data Acquisition Mode
In this mode one issued measurement command
triggers the acquisition of one data pair. Each data pair
consists of one 16 bit temperature and one 16 bit
humidity value (in this order). During transmission each
data value is always followed by a CRC checksum, see
section 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,
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Datasheet SHT3xA-DIS
medium and high) and clock stretching (enabled or
disabled).
The repeatability setting influences the measurement
duration and thus the overall energy consumption of the
sensor. This is explained in section 2.
Condition
Repeatability
Clock
stretching
Hex. code
MSB
LSB
High
06
Medium
enabled
0x2C
0D
Low
10
High
00
Medium
disabled
0x24
0B
Low
16
e.g. 0x2C06: high repeatability measurement with clock
stretching enabled
The sensor will send the temperature value first and then
the relative humidity value. After having received the
checksum for the humidity value a NACK and stop
condition has to 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 in
subsequent data, e.g. the CRC byte or the second
measurement result, in order to save time.
In case the user needs humidity and temperature data
but does not want to process CRC data, it is
recommended to read the two temperature bytes of data
with the CRC byte (without processing the CRC data);
after having read the two humidity bytes, the read
transfer 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 and
subsequently pulls down the SCL line. The SCL line is
pulled 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 Mode
In 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 this
order).
Table 8 Measurement commands in single shot mode. The
first “SCL free” block indicates a minimal waiting time of 1ms.
(Clear blocks are controlled by the microcontroller, grey
blocks by the sensor).
4.4
Readout of Measurement Results for
Single Shot Mode
After the sensor has completed the measurement, the
master 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 reception
of the read header and send two bytes of data
(temperature) followed by one byte CRC checksum and
another 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 the
sensor does not receive an ACK from the master after
any byte of data, it will not continue sending data.
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In periodic mode different measurement commands can
be selected. The corresponding 16 bit commands are
shown 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). Clock
stretching cannot be selected in this mode.
The data acquisition frequency and the repeatability
setting influences the measurement duration and the
current 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 break
command first (see section 4.8). Upon reception of the
break command the sensor will abort the ongoing
measurement and enter the single shot mode.
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Datasheet SHT3xA-DIS
Hex. code
MSB
LSB
High
32
Medium
0.5
0x20
24
Low
2F
High
30
Medium
1
0x21
26
Low
2D
High
36
Medium
2
0x22
20
Low
2B
High
34
Medium
4
0x23
22
Low
29
High
37
Medium
10
0x27
21
Low
2A
e.g. 0x2130: 1 high repeatability mps - measurement per
second
4
5
6
I2C Address
7
8
9
W
I2C write header
1
2
3
4
5
6
7
Command MSB
8
9
The ART feature can also be evaluated using the
Evaluation Kit EK-H5 from Sensirion.
Command
Hex Code
Periodic Measurement with
ART
0x2B32
2
3
4
5
6
I2C Address
7
8
9
W
I2C write header
1
2
3
4
5
6
7
Command MSB
8
9
10 11 12 13 14 15 16 17 18
Command LSB
ACK
1
S
16-bit command
Table 11 Command for a periodic data acquisition with
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
16-bit command
Table 9 Measurement commands for periodic data acquisition
mode (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
The ART (accelerated response time) feature can be
activated by issuing the command in Table 11. After
issuing the ART command the sensor will start acquiring
data with a frequency of 4Hz.
The ART command is structurally similar to any other
command in Table 9. Hence section 4.5 applies for
starting a measurement, section 4.6 for reading out data
and section 4.8 for stopping the periodic data acquisition.
ACK
3
ACK
S
2
ACK
1
ART Command
ACK
mps
4.7
ACK
Condition
Repeatability
Readout of Measurement Results for
Periodic Mode
Transmission of the measurement data can be initiated
through 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 the
communication 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 Data
0x 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 will abort the ongoing
measurement and enter the single shot mode. This takes
1ms.
Command
Hex Code
Break
0x3093
Table 12 Break command (Clear blocks are controlled by
the microcontroller, grey blocks by the sensor).
4.9
Reset
A system reset of the SHT3xA-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 internally
during 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 the
nRESET pin of the SHT3xA-DIS.
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Datasheet SHT3xA-DIS
Interface Reset
Code
0x00
0x06
1
2
3
4
5
6
7
8
S General Call Address
General Call 1st byte
The SHT3xA-DIS provides a soft reset mechanism that
forces 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
SHT3xA-DIS. 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 command
as shown in Table 13 should be sent.
It is worth noting that the sensor reloads calibration data
prior to every measurement by default.
Command
Hex Code
Soft Reset
0x30A2
0x0006
9
1
2
3
4
5
6
7
Reset Command
8
9
ACK
Soft Reset / Re-Initialization
Command
Address byte
Second byte
Reset command using the
general call address
ACK
If communication with the device is lost, the following
signal sequence will reset the serial interface: While
leaving SDA high, toggle SCL nine or more times. This
must be followed by a Transmission Start sequence
preceding the next command. This sequence resets the
interface 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).
Reset through the nReset Pin
Pulling the nReset pin low (see Table 6) generates a
reset similar to a hard reset. The nReset pin is internally
connected to VDD through a pull-up resistor and hence
active low. The nReset pin has to be pulled low for a
minimum of 1 µs to generate a reset of the sensor.
Hard Reset
Table 13 Soft reset command (Clear blocks are controlled
by the microcontroller, grey blocks by the sensor).
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 to
pins 1 (SDA), 4 (SCL) and 2 (ADDR) also needs to be
removed.
4.10 Heater
Reset through General Call
Additionally, a reset of the sensor can also be generated
using the “general call” mode according to I2C-bus
specification12. This generates a reset which is
functionally identical to using the nReset pin. It is
important to understand that a reset generated in this
way is not device specific. All devices on the same I2C
bus that support the general call mode will perform a
reset. Additionally, this command only works when the
sensor is able to process I2C commands. The
appropriate command consists of two bytes and is
shown in Table 14.
The SHT3xA is equipped with an internal heater, which
is meant for plausibility checking only. The temperature
increase achieved by the heater depends on various
parameters and lies in the range of a few degrees
centigrade. It can be switched on and off by command,
see table below. The status is listed in the status register.
After a reset the heater is disabled (default condition).
Command
Heater Enable
Heater Disabled
Hex 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 the
operational 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
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Datasheet SHT3xA-DIS
register is shown in Table 16 whereas a description of
the content can be found in Table 17.
Command
Hex code
Read Out of status register
0xF32D
All flags (Bit 15, 11, 10, 4) in the status register can be
cleared (set to zero) by sending the command shown in
Table 18.
Command
Hex Code
Clear status register
0x 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’
‘0’
‘0’
‘0’
‘0
‘0’
‘xxxxx’
‘1’
'0': no reset detected since last ‘clear
status register’ command
3:2
1
0
'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 was
either invalid, failed the integrated
command checksum
Write data checksum status
'0': checksum of last write transfer was
correct
'1': checksum of last write transfer failed
Table 17 Description of the status register.
Clear Status Register
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‘00’
‘0’
4.12 Checksum Calculation
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 of
the two previously transmitted data bytes. To calculate
the checksum only these two previously transmitted data
bytes are used.
Property
Value
Name
Width
Protected data
Polynomial
Initialization
Reflect input
Reflect output
Final XOR
Examples
CRC-8
8 bit
read and/or write data
0x31 (x8 + x5 + x4 + 1)
0xFF
False
False
0x00
CRC (0xBEEF) = 0x92
Table 19 I2C CRC properties.
4.13 Conversion of Signal Output
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 physical
scale 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):
ST
2 1
S
T F 49 315 16 T
2 1
T C 45 175
16
SRH and ST denote the raw sensor output for humidity
and temperature, respectively. The formulas work only
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Datasheet SHT3xA-DIS
correctly when SRH and ST are used in decimal
representation.
4.14 Communication Timing
Parameter
Symbol
SCL clock frequency
Hold time (repeated) START
condition
LOW period of the SCL
clock
HIGH period of the SCL
clock
fSCL
Min.
Typ.
Max.
Units
0
-
1000
kHz
0.24
-
-
µs
tLOW
0.5
-
-
µs
tHIGH
0.26
-
-
µs
-
250
300
300
0.9
ns
ns
ns
ns
ns
µs
tHD;STA
Conditions
After this period, the first
clock pulse is generated
SDA hold time
tHD;DAT
SDA set-up time
SCL/SDA rise time
SCL/SDA fall time
SDA valid time
Set-up time for a repeated
START condition
Set-up time for STOP
condition
Capacitive load on bus line
Low level input voltage
High level input voltage
Low level output voltage
tSU;DAT
tR
tF
tVD;DAT
0
0
50
-
tSU;STA
0.26
-
-
µs
tSU;STO
0.26
-
-
µs
CB
VIL
VIH
VOL
0
0.7xVDD
-
-
400
0.3xVDD
1xVDD
0.66
pF
V
V
V
3 mA sink current
Comments
Transmitting data
Receiving data
Table 20 Timing specifications for I2C communication, valid for T=-40°C … 125°C and VDD = VDDmin… VDDmax. The nomenclature
above is according to the I2C Specification (UM10204, Rev. 6, April 4, 2014).
1/fSCL
tHIGH
tR
tLOW
tF
70%
SCL
tSU;DAT
30%
tHD;DAT
DATA IN
70%
SDA
30%
tVD;DAT
tF
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 are
controlled 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 SHT3xA-DIS
5
Packaging
SHT3xA-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 a
lead frame. The latter is made of Cu plated with
Ni/Pd/Au. Chip and lead frame are overmolded by an
epoxy-based mold compound leaving the central die pad
and I/O pins exposed for mechanical and electrical
connection. 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 bottom line consists of 7 letters, with the initial A
indicating the automotive version. The two digits XY
(=DI) describe the output mode. The fourth letter (A)
represents the manufacturing year (4 = 2014, 5 = 2015,
etc). The last three digits (BCD) represent an
alphanumeric tracking code. That code can be decoded
by 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 triangular
shaped cut in the otherwise rectangular die pad. The
dimensions of the triangular cut are shown in Figure 14
through the labels T1 & T2.
The package (except for the humidity sensor opening)
follows JEDEC publication 95, design registration 4.20,
small scale plastic quad and dual inline, square and
rectangular, No-LEAD packages (with optional thermal
enhancements) small scale (QFN/SON), Issue D.01,
September 2009.
SHT 3 x
SHT3xA-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
A XYABCD
Traceability
All SHT3xA-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.
Figure 13 Top view of the SHT3xA-DIS illustrating the laser
marking.
The top line consists of the pin-1 indicator which is
located in the top left corner and the product name. The
small letter x stands for the accuracy class.
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Datasheet SHT3xA-DIS
5.2
Package Outline
Figure 14 Dimensional drawing of SHT3xA-DIS sensor package
Parameter
Package height
Leadframe height
Pad width
Package width
Center pad length
Package length
Center pad width
Pad pitch
Pad length
Symbol
Min
Nom.
Max
Units Comments
A
A3
b
D
D2
E
E2
e
L
S
0.8
0.2
2.4
1
2.4
1.7
0.25
-
0.9
0.2
0.25
2.5
1.1
2.5
1.8
0.5
0.35
-
1
0.3
2.6
1.2
2.6
1.9
0.45
1.5
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
T1xT2
-
0.3x45°
-
mm
Max cavity
Center pad marking
Only as guidance. This value includes all tolerances,
including displacement tolerances. Typically the opening
will be smaller.
indicates the position of pin 1
Table 21 Package outline.
5.3
Land Pattern
Figure 15 shows the land pattern. The land pattern is
understood 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, the
solder 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 to
have one solder mask opening for all 4 I/O pads on one
side.
www.sensirion.com
For solder paste printing it is recommended to use a
laser-cut, stainless steel stencil with electro-polished
trapezoidal 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
the
Application
Note
HT_AN_SHTxx_Assembly_of_SMD_Packages , which
can be found on the Sensirion webpage.
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Datasheet SHT3xA-DIS
Recommended Land Pattern
Recommended Stencil Aperture
2.55
0.5
1.6
0.25
0.5
0.5
1.7
0.5
0.25
0.5
0.5
2.35
0.2
1
0.3
0.55
0.9
0.55
Figure 15 Recommended metal land pattern (left) and stencil apertures (right) for the SHT3xA-DIS. The dashed lines represent the
outer 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 1
0.30 ±.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 - UNLESS
NOTED 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 POCKET
DETAIL B
Figure 16 Technical drawing of the packaging tape with sensor orientation in tape. Header tape is to the right and trailer tape to the
left on this drawing. Dimensions are given in millimeters.
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Datasheet SHT3xA-DIS
7
Quality
Qualification of the SHT3xA-DIS is performed based on
the AEC Q 100 qualification test method.
7.1
Material Contents
The device is fully RoHS and WEEE compliant, e.g. free
of Pb, Cd, and Hg.
8
Ordering Information
The SHT3xA-DIS can be ordered in tape and reel
packaging with different sizes, see Table 22. The reels
are sealed into antistatic ESD bags. The document
“SHT3x shipping package” that shows the details about
the shipping package is available upon request.
Name
SHT30A-DIS-B2.5kS
SHT30A-DIS-B10kS
SHT31A-DIS-B2.5kS
SHT31A-DIS-B10kS
SHT35A-DIS-B2.5kS
SHT35A-DIS-B10kS
Quantity
2500
10000
2500
10000
2500
10000
Order Number
3.000.364
1-101249-01
3.000.282
1-101255-01
3.000.365
1-101620-01
Table 22 SHT3xA-DIS ordering options.
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Datasheet SHT3xA-DIS
9
Further Information
For more in-depth information on the SHT3xA-DIS and its application please consult the document in Table 23.
Parameter values specified in the datasheet overrule possibly conflicting statements given in references cited in
this datasheet.
Document Name
Description
Source
SHT3x 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 STSxx Assembly of SMD
Packages
Assembly Guide (Soldering Instructions)
SHTxx STSxx 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 SHT3xA-DIS.
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Datasheet SHT3xA-DIS
Revision History
Date
Version
Page(s)
Changes
May 2015
1
All
Initial release
17. July 2015
2
5
Updated information on absolute minimum and maximum ratings
November 2015
3
All
Updated temperature specifications; correction of typos; minor refinement of
sensor parameters
January 2017
4
All
SHT35A specifications included, general makeover, minor refinement of sensor
parameters
March 2017
5
16
Pad length updated, Table 21
Land pattern drawing in Figure 15 simplified (no parameter changed)
October 2018
6
2
Improved repeatability Table 1
2
Updated T-resolution and -repeatability Table 2
6
Updated Table 3
7
Section 2.3: Introduced “Ratings are only tested each at a time.”
9
Introduced note on minimal waiting time in section 4
9
Updated Table 7
10
Updated caption Table 8
10
10
11
14
19
All
December 2019
www.sensirion.com
7
Removed “The stop condition is optional.” In section 4
Changed formulation in section 4.5 “Upon reception of the break command the
sensor will abort the ongoing measurement and enter the single shot mode.”
Changed formulation in section 4.8 to “Upon reception of the break command
the sensor will abort the ongoing measurement and enter the single shot
mode. This takes 1ms.”
Updated Table 20
Introduced “Parameter values specified in the datasheet overrule possibly
conflicting statements given in references cited in this datasheet.“ in section 9.
Typo & wording corrections etc.
1
Updated general introductory information
18
Updated available reel sizes in Table 22
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Datasheet SHT3xA-DIS
Important Notices
Warning, Personal Injury
Do not use this product as safety or emergency stop devices
or in any other application where failure of the product could
result in personal injury. Do not use this product for
applications other than 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 arising out of, directly or indirectly, any claim of personal
injury or death associated 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 sensitive
to electrostatic 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
product for a period of 12 months (one year) from the date of
delivery that this product 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 reasonable
satisfaction, 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
shall be 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 FORTH HEREIN, 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
the conditions of operation provided for in the data sheet and
proper use of the goods. SENSIRION explicitly disclaims all
warranties, express or implied, for any period during which the
goods are operated or stored 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 or incidental damages. All operating parameters,
including without limitation recommended parameters, must be
validated for each customer’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 © 2019, 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: +1 312 690 5858
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
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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
www.sensirion.com.cn/
Sensirion Taiwan Co. Ltd.
phone: +41 44 306 40 00
To find your local representative, please visit www.sensirion.com/contact
info@sensirion.com
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