Page 1
Each SHT1x is individually calibrated in a precision
humidity chamber. The calibration coefficients are
programmed into an OTP memory on the chip. These
coefficients are used to internally calibrate the signals
e and internal
voltage regulation allows for easy and fast system
integration. The tiny size and low power consumption
makes SHT1x the ultimate choice for even the most
mountable LCC (Leadless
rier) which is approved for standard reflow
soldering processes. The same sensor is also available
with pins (SHT7x) or on flex print (SHTA1).
±0.05
4.2
7
±0.05
1.83
±0.05
0.95
2.2
Datasheet SHT1x (SHT10, SHT11, SHT15)
Humidity and Temperature Sensor
• Fully calibrated
• Digital output
• Low power consumption
• Excellent long term stability
• SMD type package – reflow solderable
Product Summary
SHT1x (including SHT10, SHT11 and SHT15) is
Sensirion’s family of surface mountable relative humidity
and temperature sensors. The sensors integrate sensor
elements plus signal processing on a tiny foot print and
provide a fully calibrated digital output. A unique
capacitive sensor element is used for measuring relative
humidity while temperature is measured by a band-gap
sensor. The applied CMOSens® technology guarantees
excellent reliability and long term stability. Both sensors
are seamlessly coupled to a 14bit analog to digital
converter and a serial interface circuit. This results in
superior signal quality, a fast response time and
insensitivity to external disturbances (EMC).
from the sensors. The 2-wire serial interfac
demanding applications.
SHT1x is supplied in a surfaceChip Car
Dimensions
±0.1
1.5
±0.2
2.0
±0.1
1.5
±0.1
sensor opening 2.5
±0.1
Sensor Chip
SHT1x V4 – for which this datasheet applies – features a
version 4 Silicon sensor chip. Besides a humidity and a
temperature sensor the chip contains an amplifier, A/D
converter, OTP memory and a digital interface. V4 sensors
can be identified by the alpha-numeric traceability code on
NC
1
±0.1
2
A5Z
3
4
11
NC
NC
NC
NC
NC
±0.1
±0.2
MAX
the sensor cap – see example “A5Z” code on Figure 1.
Material Contents
While the sensor is made of a CMOS chip the sensor
housing consists of an LCP cap with epoxy glob top on an
FR4 substrate. The device is fully RoHS and WEEE
compliant, thus it is free of Pb, Cd, Hg, Cr(6+), PBB and
PBDE.
2.6
0.8
MAX
±0.1
3.3
4.93
±0.1
±0.05
Figure 1: Drawing of SHT1x sensor packaging, dimensions in
mm (1mm = 0.039inch). Sensor label gives “11” for SHT11 as
an example. Contacts are assigned as follows: 1:GND, 2:DATA,
3:SCK, 4:VDD.
Evaluation Kits
For sensor trial measurements, for qualification of the
sensor or even experimental application of the sensor
there is an evaluation kit EK-H2 available including sensor,
hard and software to interface with a computer.
For more sophisticated and demanding measurements a
multi port evaluation kit EK-H3 is available which allows for
parallel application of up to 20 sensors.
Version 4.0 – July 2008
Page 2
Datasheet SHT1x
Sensor Performance
Relative Humidity
123
Temperature45
Parameter Condition min typ max Units
Resolution 1
0.4 0.05 0.05 %RH
8 12 12 bit
Accuracy 2
SHT10
Accuracy 2
SHT11
Accuracy 2
SHT15
typical
maximal see Figure 2
typical
maximal see Figure 2
typical
maximal see Figure 2
Repeatability
±4.5
±3.0
±2.0
±0.1
Replacement fully interchangeable
Hysteresis
Nonlinearity
raw data
±1
±3
%RH
%RH
%RH
%RH
%RH
%RH
linearized <<1 %RH
Response time 3
τ (63%)
8 s
Operating Range 0 100 %RH
Long term drift 4 normal < 0.5 %RH/yr
± 10
± 8
± 6
RH (%RH)
± 4
∆
∆
∆
∆
± 2
± 0
0 10 20 30 40 50 60 70 80 90 100
SHT10
SHT11
SHT15
Relative Humidity (%RH)
Figure 2: Maximal RH-accuracy at 25°C per sensor type.
Parameter Condition min typ max Units
Resolution 1
0.04 0.01 0.01 °C
12 14 14 bit
Accuracy 2
SHT10
Accuracy 2
SHT11
Accuracy 2
SHT15
typical
maximal see Figure 3
typical
maximal see Figure 3
typical
maximal see Figure 3
Repeatability
±0.5
±0.4
±0.3
±0.1
°C
°C
°C
°C
Replacement fully interchangeable
Operating Range
-40 123.8 °C
-40 254.9 °F
Response Time
6
τ (63%)
5 30 s
Long term drift < 0.04 °C/yr
± 3.0
± 2.5
± 2.0
± 1.5
T (°C)
∆
∆
∆
∆
± 1.0
± 0.5
± 0.0
Figure 3: Maximal T-accuracy per sensor type.
SHT10
SHT11
SHT15
-40 -20 0 20 40 60 80 100
Temperature (°C)
Electrical and General Items
Parameter Condition min typ max Units
Source Voltage 2.4 3.3 5.5 V
Power
Consumption 5
Communication digital 2-wire interface, see Communication
Storage 10 – 50°C (0 – 125°C peak), 20 – 60%RH
sleep 2 5 µW
measuring 3 mW
average 150 µW
Packaging Information
Sensor Type Packaging Quantity Order Number
SHT10 Tape & Reel 2000 1-100218-04
Tape & Reel 100 1-100051-04
SHT11
SHT15
Tape & Reel 400 1-100098-04
Tape & Reel 2000 1-100524-04
Tape & Reel 100 1-100085-04
Tape & Reel 400 1-100093-04
1
The default measurement resolution of is 14bit for temperature and 12bit for
humidity. It can be reduced to 12/8bit by command to status register.
2
Accuracies are tested at Outgoing Quality Control at 25°C (77°F) and 3.3V.
Values exclude hysteresis and non-linearity.
3
Time for reaching 63% of a step function, valid at 25°C and 1 m/s airflow.
www.sensirion.com Version 4.0 – July 2008 2/11
4
Value may be higher in environments with high contents of volatile organic
compounds. See Section 1.3 of Users Guide.
5
Values for VDD=5.5V at 25°C, average value at one 12bit measurement
per second.
6
Response time depends on heat capacity of and thermal resistance to
sensor substrate.
Page 3
Normal
1.27
0.80
1.38
2.47
1.07
Ø0.60
1.27
7.47
0.8
4.61
1.27
1.27
1.27
7.50
Temperature
Time
TP
TL
TS (max)
preheating
critical zone
Users Guide SHT1x
1 Application Information
1.1 Operating Conditions
Sensor works stable within recommended normal range –
see Figure 4. Long term exposures to conditions outside
normal range may temporarily offset the RH signal (+3
%RH after 60h). After return to normal range it will slowly
return towards calibration state by itself. See Section 1.4.
“Reconditioning Procedure” to accelerate eliminating the
offset. Prolonged exposure to extreme conditions may
accelerate ageing.
100
80
60
40
20
Relative Humidity (%)
Max. Range
0
-40 -20 0 20 40 60 80 100 120
Figure 4: Operating Conditions
Range
Temperature (°C)
1.2 Soldering instructions
For soldering SHT1x standard reflow soldering ovens may
be used. The sensor is qualified to withstand soldering
profile according to IPC/JEDEC J-STD-020C with peak
temperatures at 260°C during up to 40sec including Pbfree assembly in IR/Convection reflow ovens.
IMPORTANT: After soldering the devices should be stored
at >75%RH for at least 12h to allow the polymer to rehydrate. Otherwise the sensor may read an offset that
slowly disappears if exposed to ambient conditions.
In no case, neither after manual nor reflow soldering, a
board wash shall be applied. Therefore it is strongly
recommended to use “no-clean” solder paste. In case of
application with exposure of the sensor to corrosive gases
the soldering pads shall be sealed to prevent loose
contacts or short cuts.
For the design of the SHT1x footprint it is recommended to
use dimensions according to Figure 7. Sensor pads are
coated with 35µm Cu, 5µm Ni and 0.1µm Au.
1.97
Figure 6: Rear side electrodes of sensor, view from top side.
t
P
t
L
No copper in this field
1.8
3.48
7.08
1.8
Figure 7: Recommended footprint for SHT1x. Values in mm.
Figure 5: Soldering profile according to JEDEC standard. TP <=
260°C and tP < 40sec for Pb-free assembly. TL < 220°C and tL <
150sec. Ramp-up/down speeds shall be < 5°C/sec.
1.3 Storage Conditions and Handling Instructions
It is of great importance to understand that a humidity
sensor is not a normal electronic component and needs to
For soldering in Vapor Phase Reflow (VPR) ovens the
peak conditions are limited to TP < 233°C during tP <
60sec and ramp-up/down speeds shall be limited to
10°C/sec. For manual soldering contact time must be
limited to 5 seconds at up to 350°C7.
be handled with care. Chemical vapors at high
concentration in combination with long exposure times
may offset the sensor reading.
For these reasons it is recommended to store the sensors
in original packaging including the sealed ESD bag at
following conditions: Temperature shall be in the range of
7
233°C = 451°F, 260°C = 500°F, 350°C = 662°F
Version 4.0 – July 2008
10°C – 50°C (0 – 125°C for limited time) and humidity at
20 – 60%RH (sensors that are not stored in ESD bags).
Page 4
A5Z
11
Datasheet SHT1x
For sensors that have been removed from the original
packaging we recommend to stored them in ESD bags
made of PE-HD8.
In manufacturing and transport the sensors shall be
1.6 Light
The SHT1x is not light sensitive. Prolonged direct
exposure to sunshine or strong UV radiation may age the
housing.
prevented of high concentration of chemical solvents and
long exposure times. Out-gassing of glues, adhesive tapes
and stickers or out-gassing packaging material such as
bubble foils, foams, etc. shall be avoided. Manufacturing
area shall be well ventilated.
For more detailed information please consult the
document “Handling Instructions” or contact Sensirion.
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
1.7 Membranes
SHT1x does not contain a membrane at the sensor
opening. However, a membrane may be added to prevent
dirt and droplets from entering the housing and to protect
the sensor. It will also reduce peak concentrations of
chemical vapors. For optimal response times the air
volume behind the membrane must be kept minimal.
Sensirion recommends and supplies the SF1 filter cap for
optimal IP54 protection (for higher protection – i.e. IP67 SF1 must be sealed to the PCB with epoxy). Please
compare Figure 9.
membrane
o-ring
Baking: 100 – 105°C at < 5%RH for 10h
Re-Hydration: 20 – 30°C at ~ 75%RH for 12h 9.
housing
1.5 Temperature Effects
Relative humidity reading strongly depends on
SHT1x
temperature. Therefore, it is essential to keep humidity
sensors at the same temperature as the air of which the
relative humidity is to be measured. In case of testing or
qualification the reference sensor and test sensor must
show equal temperature to allow for comparing humidity
readings.
If the SHT1x shares a PCB with electronic components
that produce heat it should be mounted in a way that
prevents heat transfer or keeps it as low as possible.
Measures to reduce heat transfer can be ventilation,
reduction of copper layers between the SHT1x and the
rest of the PCB or milling a slit into the PCB around the
sensor (see Figure 8).
Figure 9: Side view of SF1 filter cap mounted between PCB and
housing wall. Volume below membrane is kept minimal.
1.8 Materials Used for Sealing / Mounting
Many materials absorb humidity and will act as a buffer
increasing response times and hysteresis. Materials in the
vicinity of the sensor must therefore be carefully chosen.
Recommended materials are: Any metals, LCP, POM
PCB
Melted plastic pin
(Delrin), PTFE (Teflon), PE, PEEK, PP, PB, PPS, PSU,
PVDF, PVF.
For sealing and gluing (use sparingly): High filled epoxy for
electronic packaging (e.g. glob top, underfill), and Silicone.
Out-gassing of these materials may also contaminate the
SHT1x (see Section 1.3). Therefore try to add the sensor
as a last manufacturing step to the assembly, store the
assembly well ventilated after manufacturing or bake at
Figure 8: Top view of example of mounted SHT1x with slits
milled into PCB to minimize heat transfer.
>50°C for 24h to outgas contaminants before packing.
1.9 Wiring Considerations and Signal Integrity
Carrying the SCK and DATA signal parallel and in close
Furthermore, there are self-heating effects in case the
measurement frequency is too high. Please refer to
Section 3.3 for detailed information.
proximity (e.g. in wires) for more than 10cm may result in
cross talk and loss of communication. This may be
resolved by routing VDD and/or GND between the two
data signals and/or using shielded cables. Furthermore,
8
For example, please check www.sirel.ch
9
75%RH can conveniently be generated with saturated NaCl solution.
100 – 105°C correspond to 212 – 221°F, 20 – 30°C correspond to 68 – 86°F
www.sensirion.com Version 4.0 – July 2008 4/11
slowing down SCK frequency will possibly improve signal
integrity. Power supply pins (VDD, GND) must be
decoupled with a 100nF capacitor if wires are used.
Page 5
A5Z
NC
NC
NC
NC
NC
NC
1
2
3
4
DATA
SCK
VDD
R
P
A5Z
10
k
Ω
Datasheet SHT1x
Capacitor should be placed as close to the sensor as
possible. Please see the Application Note “ESD, Latchup
and EMC” for more information.
2.3 Serial data (DATA)
The DATA tri-state pin is used to transfer data in and out
of the sensor. For sending a command to the sensor,
DATA is valid on the rising edge of the serial clock (SCK)
1.10 ESD (Electrostatic Discharge)
ESD immunity is qualified according to MIL STD 883E,
method 3015 (Human Body Model at ±2 kV).
Latch-up immunity is provided at a force current of
±100mA with T
= 80°C according to JEDEC78A. See
amb
Application Note “ESD, Latchup and EMC” for more
information.
and must remain stable while SCK is high. After the falling
edge of SCK DATA may be changed. For safe
communication DATA valid shall be extended TSU and THO
before the rising and after the falling edge of SCK,
respectively – see Figure 11. For reading data from the
sensor, DATA is valid TV after SCK has gone low and
remains valid until the next falling edge of SCK.
To avoid signal contention the microcontroller must only
drive DATA low. An external pull-up resistor (e.g. 10kΩ) is
2 Interface Specifications
required to pull the signal high – it should be noted that
pull-up resistors may be included in I/O circuits of
Pin Name Comment
1 GND Ground
2 DATA Serial Data, bidirectional
3 SCK Serial Clock, input only
11
4 VDD Source Voltage
NC NC Must be left unconnected
Table 1: SHT1x pin assignment, NC remain floating.
2.1 Power Pins (VDD, GND)
The supply voltage of SHT1x must be in the range of 2.4 –
5.5V, recommended supply voltage is 3.3V. Power supply
pins Supply Voltage (VDD) and Ground (GND) must be
decoupled with a 100 nF capacitor – see Figure 10.
The serial interface of the SHT1x is optimized for sensor
readout and effective power consumption. The sensor
cannot be addressed by I2C protocol, however, the sensor
can be connected to an I2C bus without interference with
other devices connected to the bus. The controller must
switch between the protocols.
VDD
GND
SHT1x
Micro-
Controller
(Master)
100nF
2.4 – 5.5V
GND
Figure 10: Typical application circuit, including pull up resistor
RP and decoupling of VDD and GND by a capacitor.
11
(Slave)
microcontrollers. See Table 2 for detailed I/O characteristic
of the sensor.
2.4 Electrical Characteristics
The electrical characteristics such as power consumption,
low and high level, input and output voltages depend on
the supply voltage. Table 2 gives electrical characteristics
of SHT1x with the assumption of 5V supply voltage if not
stated otherwise. For proper communication with the
sensor it is essential to make sure that signal design is
strictly within the limits given in Table 3 and Figure 11.
Parameter Conditions min typ max Units
Power supply DC
Supply current
Low level output
voltage
High level output
voltage
Low level input
voltage
High level input
voltage
Input current on
pads
Output current
Table 2: SHT1x DC characteristics. RP stands for pull up
resistor, while IOL is low level output current.
10
2.4 3.3 5.5 V
measuring 0.55 1 mA
average11 2 28 µA
sleep 0.3 1.5 µA
IOL < 4 mA 0 250 mV
RP < 25 kΩ 90% 100% VDD
Negative going 0% 20% VDD
Positive going 80% 100% VDD
1 µA
on 4 mA
Tri-stated (off) 10 20 µA
2.2 Serial clock input (SCK)
SCK is used to synchronize the communication between
microcontroller and SHT1x. Since the interface consists of
fully static logic there is no minimum SCK frequency.
www.sensirion.com Version 4.0 – July 2008 5/11
10
Recommended voltage supply for highest accuracy is 3.3V, due to sensor
calibration.
11
Minimum value with one measurement of 8 bit accuracy without OTP reload
per second, typical value with one measurement of 12bit accuracy per
second.
Page 6
us
DATA
SCK
10%
10%
DATA
SCK
10%
10%
Datasheet SHT1x
T
SCK
T
SCKH
T
SCKL
T
R
T
F
90%
90%
T
SU
DATA valid write
T
HO
DATA valid read
T
V
90%
T
RO
T
FO
90%
Figure 12: "Transmission Start" sequence
Figure 11: Timing Diagram, abbreviations are explained in
Table 3. Bold DATA line is controlled by the sensor, plain DATA
line is controlled by the micro-controller. Both valid times refer to
the left SCK toggle.
Parameter Conditions min typ max Units
VDD > 4.5V 0 0.1 5 MHz
F
SCK Frequency
SCK
VDD < 4.5V 0 0.1 1 MHz
T
SCK hi/low time 100 ns
SCKx
TR/T
SCK rise/fall time 1 200 * ns
F
OL = 5pF 3.5 10 20 ns
TFO DATA fall time
OL = 100pF 30 40 200 ns
TRO DATA rise time ** ** ** ns
TV DATA valid time 200 250 *** ns
TSU DATA setup time 100 150 *** ns
THO DATA hold time 10 15 **** ns
* T
** T
*** T
**** T
+ T
= (F
)-1 – T
R_max
F_max
SCK
is determined by the RP*C
R0
and T
V_max
line capacitance (Cbus) at DATA line
< TV – max (TR0, TF0)
H0_max
depend on external pull-up resistor (RP) and total b
SU_max
– T
SCKH
time-constant at DATA line
bus
SCKL
Table 3: SHT1x I/O signal characteristics, OL stands for Output
Load, entities are displayed in Figure 11.
3 Communication with Sensor
3.1 Start up Sensor
As a first step the sensor is powered up to chosen supply
voltage VDD. The slew rate during power up shall not fall
below 1V/ms. After power-up the sensor needs 11ms to
get to Sleep State. No commands must be sent before
that time.
3.2 Sending a Command
To initiate a transmission, a Transmission Start sequence
has to be issued. It consists of a lowering of the DATA line
while SCK is high, followed by a low pulse on SCK and
raising DATA again while SCK is still high – see Figure 12.
www.sensirion.com Version 4.0 – July 2008 6/11
The subsequent command consists of three address bits
(only ‘000’ is supported) and five command bits. The
SHT1x indicates the proper reception of a command by
pulling the DATA pin low (ACK bit) after the falling edge of
the 8th SCK clock. The DATA line is released (and goes
high) after the falling edge of the 9th SCK clock.
Command Code
Reserved 0000x
Measure Temperature 00011
Measure Relative Humidity 00101
Read Status Register 00111
Write Status Register 00110
Reserved 0101x-1110x
Soft reset, resets the interface, clears the
11110
status register to default values. Wait minimum
11 ms before next command
Table 4: SHT1x list of commands
3.3 Measurement of RH and T
After issuing a measurement command (‘00000101’ for
relative humidity, ‘00000011’ for temperature) the
controller has to wait for the measurement to complete.
This takes a maximum of 20/80/320 ms for a 8/12/14bit
measurement. The time varies with the speed of the
internal oscillator and can be lower by up to 30%. To
signal the completion of a measurement, the SHT1x pulls
data line low and enters Idle Mode. The controller must
wait for this Data Ready signal before restarting SCK to
readout the data. Measurement data is stored until
readout, therefore the controller can continue with other
tasks and readout at its convenience.
Two bytes of measurement data and one byte of CRC
checksum (optional) will then be transmitted. The micro
controller must acknowledge each byte by pulling the
DATA line low. All values are MSB first, right justified (e.g.
the 5th SCK is MSB for a 12bit value, for a 8bit result the
first byte is not used).
Communication terminates after the acknowledge bit of
the CRC data. If CRC-8 checksum is not used the
controller may terminate the communication after the
measurement data LSB by keeping ACK high. The device
automatically returns to Sleep Mode after measurement
and communication are completed.
Page 7
DATA
SCK
10%
10%
3
9
DATA
DATA
SCK
SCK
SCK
DATA
A2 A1
A0 C4 C3 C2 C1 C0 ACK
15 14 13 12 11 10 9 8 ACK 7 6 5 4 3 2 1 0 ACK
7 6 5 4 3
2 1 0 ACK
Transmission Start
Address = ‘000
’ Command = ‘00101
’
12bit Humidity Data
CRC-8 Checksum
Transmission Start
Sleep
(wait for next
Idle Bits
Skip ACK to end trans
-
Sensor pulls DATA line low after
MSb LSb
MSb
LSb
Datasheet SHT1x
Important: To keep self heating below 0.1°C, SHT1x
should not be active for more than 10% of the time – e.g.
maximum one measurement per second at 12bit accuracy
shall be made.
Status Register
Some of the advanced functions of the SHT1x such as
selecting measurement resolution, end of battery notice or
using the heater may be activated by sending a command
to the status register. The following section gives a brief
3.4 Connection reset sequence
If communication with the device is lost the following signal
sequence will reset the serial interface: While leaving
DATA high, toggle SCK nine or more times – see Figure
13. 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.
1 2
4 - 8
90%
overview of these features. A more detailed description is
available in the Application Note “Status Register”.
After the command Status Register Read or Status
Register Write – see Table 4 – the content of 8 bits of the
status register may be read out or written. For the
communication compare Figures 16 and 17 – the
assignation of the bits is displayed in Table 5.
0 0 0 0 0 1 1 0
TS
Status Register
Bit 7
ACK
ACK
Transmission Start
90%
Figure 13: Connection Reset Sequence
3.5 CRC-8 Checksum calculation
The whole digital transmission is secured by an 8bit
checksum. It ensures that any wrong data can be detected
and eliminated. As described above this is an additional
feature of which may be used or abandoned.
Please consult Application Note “CRC-8 Checksum
Calculation” for information on how to calculate the CRC.
A2 A1 A0 C4 C3 C2 C1 C0
Figure 14: Status Register Write
0 0 0 0 0 1 1 1
TS
Status Register Checksum
Bit 7
ACK
Bit 7
ACK
ACK
Figure 15: Status Register Read
Examples of full communication cycle are displayed in
Figures 15 and 16.
0 0 0 Command 0 0 MSB
TS
Wait for
DATA ready
ACK
LSB Checksum
Figure 16: Overview of Measurement Sequence. TS = Transmission Start, MSB = Most Significant Byte, LSB = Last
Significant Byte, LSb = Last Significant Bit.
LSb
ACK
Measurement (80ms for 12bit)
ACK
completion of measurement
ACK
15 14 13 12 11 10 9 8 ACK
7 6 5 4 3 2 1 0 ACK
7 6 5 4 3 2 1 0 ACK
measurement)
Skip ACK to end transmission
Figure 17: Example RH measurement sequence for value “0000’1001“0011’0001” = 2353 = 75.79 %RH (without temperature
compensation). DATA valid times are given and referenced in boxes on DATA line. Bold DATA lines are controlled by sensor while plain
lines are controlled by the micro-controller.
www.sensirion.com Version 4.0 – July 2008 7/11
mission (if no CRC is used)
Page 8
()(
)
Datasheet SHT1x
Bit Type Description Default
7 reserved 0
End of Battery (low voltage
6 R
5 reserved 0
4 reserved 0
3 For Testing only, do not use 0
2 R/W Heater 0 off
1 R/W no reload from OTP 0 reload
0 R/W
detection)
‘0’ for VDD > 2.47
‘1’ for VDD < 2.47
’1’ = 8bit RH / 12bit Temp.
resolution
’0’ = 12bit RH / 14bit Temp.
resolution
No default value,
bit is only updated
X
after a
measurement
12bit RH
0
14bit Temp.
SORH c1 c2 c3
12 bit -2.0468 0.0367 -1.5955E-6
8 bit -2.0468 0.5872 -4.0845E-4
Table 6: Optimized V4 humidity conversion coefficients
The values given in Table 6 are newly introduced and
provide optimized accuracy for V4 sensors along the full
measurement range. The parameter set cx*, which has
been proposed in earlier datasheets, which was optimized
for V3 sensors, still applies to V4 sensors and is given in
Table 7 for reference.
SORH c1* c2* c3*
12 bit -4.0000 0.0405 -2.8000E-6
8 bit -4.0000 0.6480 -7.2000E-4
Table 5: Status Register Bits
Table 7: V3 humidity conversion coefficients, which also apply
to V4.
Measurement resolution: The default measurement
resolution of 14bit (temperature) and 12bit (humidity) can
be reduced to 12 and 8bit. This is especially useful in high
speed or extreme low power applications.
For simplified, less computation intense conversion
formulas see Application Note “RH and Temperature NonLinearity Compensation”. Values higher than 99% RH
indicate fully saturated air and must be processed and
End of Battery function detects and notifies VDD voltages
below 2.47 V. Accuracy is ±0.05 V.
Heater: An on chip heating element can be addressed by
writing a command into status register. The heater may
increase the temperature of the sensor by 5 – 10°C12
beyond ambient temperature. The heater draws roughly
8mA @ 5V supply voltage.
For example the heater can be helpful for functionality
analysis: Humidity and temperature readings before and
after applying the heater are compared. Temperature shall
displayed as 100%RH13. Please note that the humidity
sensor has no significant voltage dependency.
100%
80%
60%
40%
20%
0%
Relative Humidity
0 500 1000 1500 2000 2500 3000 3500
SORH sensor readout (12bit)
increase while relative humidity decreases at the same
time. Dew point shall remain the same.
Please note: The temperature reading will display the
temperature of the heated sensor element and not
ambient temperature. Furthermore, the sensor is not
qualified for continuous application of the heater.
Figure 18: Conversion from SORH to relative humidity
4.2 Temperature compensation of Humidity Signal
For temperatures significantly different from 25°C (~77°F)
the humidity signal requires a temperature compensation.
The temperature correction corresponds roughly to
0.12%RH/°C @ 50%RH. Coefficients for the temperature
4 Conversion of Signal Output
4.1 Relative Humidity
For compensating non-linearity of the humidity sensor –
see Figure 18 – and for obtaining the full accuracy of the
sensor it is recommended to convert the humidity readout
(SORH) with the following formula with coefficients given in
Table 6:
2
SOcSOccRH ⋅+⋅+=
(%RH)
RH3RH21linear
12
Corresponds to 9 – 18°F
www.sensirion.com Version 4.0 – July 2008 8/11
compensation are given in Table 8.
°
SORH t1 t2
12 bit 0.01 0.00008
8 bit 0.01 0.00128
Table 8: Temperature compensation coefficients14
RHSOtt25TRH +⋅+⋅−=
linearRH21Ctrue
13
If wetted excessively (strong condensation of water on sensor surface),
sensor output signal can drop below 100%RH (even below 0%RH in some
cases), but the sensor will recover completely when water droplets
evaporate. The sensor is not damaged by water immersion or condensation.
14
Coefficients apply both to V3 as well as to V4 sensors.
Page 9
Datasheet SHT1x
4.3 Temperature
5 Environmental Stability
The band-gap PTAT (Proportional To Absolute
Temperature) temperature sensor is very linear by design.
Use the following formula to convert digital readout (SOT)
to temperature value, with coefficients given in Table 9:
SOddT ⋅+=
T21
VDD d1 (°C) d1 (°F) SOT d2 (°C) d2 (°F)
5V -40.1 -40.2 14bit 0.01 0.018
4V -39.8 -39.6 12bit 0.04 0.072
3.5V -39.7 -39.5
3V -39.6 -39.3
2.5V -39.4 -38.9
Table 9: Temperature conversion coefficients15.
4.4 Dew Point
SHT1x is not measuring dew point directly, however dew
If sensors are qualified for assemblies or devices, please
make sure that they experience same conditions as the
reference sensor. It should be taken into account that
response times in assemblies may be longer, hence
enough dwell time for the measurement shall be granted.
For detailed information please consult Application Note
“Qualification Guide”.
The SHT1x sensor series were tested according to AECQ100 Rev. F qualification test method. Sensor
specifications are tested to prevail under the AEC-Q100
temperature grade 2 test conditions listed in Table 1116.
Sensor performance under other test conditions cannot be
guaranteed and is not part of the sensor specifications.
Especially, no guarantee can be given for sensor
performance in the field or for customer’s specific
application.
Please contact Sensirion for detailed information.
point can be derived from humidity and temperature
readings. Since humidity and temperature are both
measured on the same monolithic chip, the SHT1x allows
superb dew point measurements.
For dew point (Td) calculations there are various formulas
to be applied, most of them quite complicated. For the
temperature range of -40 – 50°C the following
approximation provides good accuracy with parameters
given in Table 10:
Tm
⋅
+
TT
+
n
−
Tm
⋅
TT
+
n
( )
RH
100%
RH
100%
ln
TTRH,T
⋅=
nd
lnm
−
Temperature Range Tn (°C) m
Above water, 0 – 50°C 243.12 17.62
Above ice, -40 – 0°C 272.62 22.46
Environment Standard Results17
HTSL 125°C, 1000 hours Within
specifications
TC -50°C - 125°C, 1000 cycles
Acc. JESD22-A104-C
UHST 130°C / 85%RH, 96h Within
THU 85°C / 85%RH, 1000h Within
ESD immunity MIL STD 883E, method 3015
(Human Body Model at ±2kV)
Latch-up force current of ±100mA with
T
= 80°C, acc. JEDEC 17
amb
Table 11: Qualification tests: HTSL = High Temperature Storage
Lifetime, TC = Temperature Cycles, UHST = Unbiased Highly
accelerated temperature and humidity Test, THU = Temperature
humidity unbiased
Within
specifications
specifications
specifications
Qualified
Qualified
6 Packaging
Table 10: Parameters for dew point (Td) calculation.
Please note that “ln(…)” denotes the natural logarithm. For
RH and T the linearized and compensated values for
relative humidity and temperature shall be applied.
For more information on dew point calculation see
Application Note “Dew point calculation”.
6.1 Packaging type
SHT1x are supplied in a surface mountable LCC
(Leadless Chip Carrier) type package. The sensor housing
consists of a Liquid Crystal Polymer (LCP) cap with epoxy
glob top on a standard 0.8mm FR4 substrate. The device
is fully RoHS and WEEE compliant – it is free of of Pb, Cd,
Hg, Cr(6+), PBB and PBDE.
15
Temperature coefficients have slightly been adjusted compared to datasheet
SHTxx version 3.01. Coefficients apply to V3 as well as V4 sensors.
www.sensirion.com Version 4.0 – July 2008 9/11
16
Sensor operation temperature range is -40 to 105°C according to AEC-Q100
temperature grade 2.
17
According to accuracy and long term drift specification given on Page 2.
Page 10
1.75
± 0.
10
5.50
± 0.
05
12.0
± 0.
3
5.80
A5Z
11
Datasheet SHT1x
Device size is 7.47 x 4.93 x 2.5 mm (0.29 x 0.19 x 0.1
inch), see Figure 1, weight is 100 mg.
6.3 Shipping Package
SHT1x are shipped in 12mm tape at 100pcs, 400pcs and
2000pcs – for details see Figure 21 and Table 12. Reels
6.2 Traceability Information
All SHT1x are marked with an alphanumeric, three digit
code on the chip cap (for reference: V3 sensors were
labeled with numeric codes) – see “A5Z” on Figure 1. The
lot numbers allow full traceability through production,
calibration and testing. No information can be derived from
the code directly, respective data is stored at Sensirion
and is provided upon request.
Labels on the reels are displayed in Figures 19 and 20,
they both give traceability information.
Lot No.: XX0-04-YRRRRTTTT
Quantity: RRRR
RoHS: Compliant
Lot No.
are individually labeled with barcode and human readable
labels.
Sensor Type Packaging Quantity Order Number
SHT10 Tape & Reel 2000 1-100218-04
Tape & Reel 100 1-100051-04
SHT11
Tape & Reel 400 1-100098-04
Tape & Reel 2000 1-100524-04
SHT15
Tape & Reel 100 1-100085-04
Tape & Reel 400 1-100093-04
Table 12: Packaging types per sensor type.
Dimensions of packaging tape is given in Figure 21. All
tapes have a minimum of 480mm empty leader tape (first
pockets of the tape) and a minimum of 300mm empty
trailer tape (last pockets of the tape).
Figure 19: First label on reel: XX = Sensor Type (11 for SHT11),
04 = Chip Version (V4), Y = last digit of year, RRRR = number of
sensors on reel, TTTT = Traceability Code.
0.30 ± 0.05
R0.3 MAX
2.00 ± 0.05
1.00
12.00
Ø1.50 MIN
Ø1.50 MIN
Device Type: 1-100PPP-04
Description: Humidity & Temperature Sensor
SHTxx
Part Order No. 1-100PPP-04 or Customer Number
Date of Delivery: DD.MM.YYYY
Order Code: 45CCCC / 0
Figure 20: Second label on reel: For Device Type and Part
Order Number please refer to Table 12, Delivery Date (also
Date Code) is date of packaging of sensors (DD = day, MM =
month, YYYY = year), CCCC = Sensirion order number.
2.80
8.20
R0.5 TYP
Figure 21: Tape configuration and unit orientation within tape,
dimensions in mm (1mm = 0.039inch). The leader tape is at the
right side of the figure while the trailer tape is to the left
(direction of unreeling).
www.sensirion.com Version 4.0 – July 2008 10/11
Page 11
Datasheet SHT1x
Revision History
Date Version Page(s) Changes
March 2007 3.0 1 – 10 Data sheet valid for SHTxx-V4 and SHTxx-V3
August 2007 3.01 1 – 10 Electrical characteristics added, measurement time corrected
July 2008 4.0 1 – 10 New release, rework of datasheet
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© 2007, SENSIRION.
CMOSens® is a trademark of Sensirion
All rights reserved
Headquarter and Sales Offices
Headquarter Sales Office USA:
SENSIRION AG Phone: + 41 (0)44 306 40 00 SENSIRION Inc. Phone: 805 409 4900
Laubisruetistr. 50 Fax: + 41 (0)44 306 40 30 2801 Townsgate Rd., Suite 240 Fax: 805 435 0467
CH-8712 Staefa ZH info@sensirion.com Westlake Village, CA 91361 michael.karst@sensirion.com
Switzerland http://www.sensirion.com/ USA http://www.sensirion.com/
Sales Office Korea: Sales Office Japan:
SENSIRION KOREA Co. Ltd. Phone: 031 440 9925~27 SENSIRION JAPAN Co. Ltd. Phone: 03 3444 4940
#1414, Anyang Construction Tower B/D, Fax: 031 440 9927 Postal Code: 108-0074 Fax: 03 3444 4939
1112-1, Bisan-dong, Anyang-city info@sensirion.co.kr Shinagawa Station Bldg. 7F, info@sensirion.co.jp
Gyeonggi-Province http://www.sensirion.co.kr 4-23-5, Takanawa, Minato-ku http://www.sensirion.co.jp
South Korea
Find your local representative at: http://www.sensirion.com/reps
www.sensirion.com Version 4.0 – July 2008 11/11
Tokyo, Japan
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