1-100085-04 - Sensitron Semiconductor

www.sensirion.com Version 4.3 – May 2010 1/11

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

Dimensions

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.

Sensor Chip

SHT1x V4 – for which this datasheet applies – features a

version 4 Silicon sensor chip. Besides the humidity and

temperature sensors 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

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.

Evaluation Kits

For sensor trial measurements, for qualification of the

sensor or even experimental application (data logging) of

the sensor there is an evaluation kit EK-H4 available

including SHT71 (same sensor chip as SHT1x) and 4

sensor channels, hard and software to interface with a

computer. For other evaluation kits please check

www.sensirion.com/humidity.

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).

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

from the sensors. The 2-wire

serial interface 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

demanding applications.

SHT1x is supplied in a surface-mountable LCC (L

eadless

Chip Carrier) which is approved for standard reflow

soldering processes. The same sensor is also available

with pins (SHT7x) or on flex print (SHTA1).

A5Z

1

2

NC

3.3

±0.1

4.93

±0.05

2.0

±0.1

1.5

±0.1

7.47

±0.05

4.2

±0.1

1.2

7

±0.05

1.83

±0.05

5.2

±0.2

0.6

±0.1

s

ensor opening

2.5 ±0.1

0.8

±0.1

3

4

11

0.95

±0.1

1.5 ±0.2

2.6

MAX

2.2 MAX

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 2/11

Sensor Performance

Relative Humidity123

Parameter Condition min typ max Units

0.4 0.05 0.05 %RH

Resolution 1 8 12 12 bit

typical 4.5 %RH

Accuracy 2

SHT10 maximal see Figure 2

typical 3.0 %RH

Accuracy 2

SHT11 maximal see Figure 2

typical 2.0 %RH

Accuracy 2

SHT15 maximal see Figure 2

Repeatability 0.1 %RH

Hysteresis 1 %RH

Non-linearity linearized <<1 %RH

Response time 3  (63%) 8 s

Operating Range

0 100 %RH

Long term drift 4 normal < 0.5 %RH/yr

SHT11

SHT15

SHT10

± 0

± 2

± 4

± 6

± 8

± 10

0 10 20 30 40 50 60 70 80 90 100

Relative Humidity (%RH)

RH (%RH)

Figure 2: Maximal RH-tolerance at 25°C per sensor type.

Electrical and General Items

Parameter Condition min typ max Units

Source Voltage 2.4 3.3 5.5 V

sleep 2 5 µW

measuring 3 mW

Power

Consumption 5 average 90 µW

Communication digital 2-wire interface, see Communication

Storage 10 – 50°C (0 – 125°C peak), 20 – 60%RH

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 are applicable to non-condensing environments

only.

3 Time for reaching 63% of a step function, valid at 25°C and 1 m/s airflow.

Temperature45

Parameter Condition min typ max Units

0.04 0.01 0.01 °C

Resolution 1 12 14 14 bit

typical 0.5 °C

Accuracy 2

SHT10 maximal see Figure 3

typical 0.4 °C

Accuracy 2

SHT11 maximal see Figure 3

typical 0.3 °C

Accuracy 2

SHT15 maximal see Figure 3

Repeatability 0.1 °C

-40 123.8

°C

Operating Range

-40 254.9

°F

Response Time 6

 (63%) 5 30 s

Long term drift < 0.04

°C/yr

SHT11

SHT15

SHT10

± 0.0

± 0.5

± 1.0

± 1.5

± 2.0

± 2.5

± 3.0

-40 -20 0 20 40 60 80 100

Temperature (°C)

T (°C)

Figure 3: Maximal T-tolerance per sensor type.

Packaging Information

Sensor Type Packaging Quantity Order Number

SHT10 Tape & Reel 2000 1-100218-04

Tape & Reel 100 1-100051-04

Tape & Reel 400 1-100098-04

SHT11 Tape & Reel 2000 1-100524-04

Tape & Reel 100 1-100085-04

SHT15 Tape & Reel 400 1-100093-04

This datasheet is subject to change and may be

amended without prior notice.

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=3.3V 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.

www.sensirion.com Version 4.3 – May 2010 3/11

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, especially at humidity >80%RH, 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.

Max. Range

Normal

Range

0

20

40

60

80

100

-40 -20 0 20 40 60 80 100 120

Temperature (°C)

Relative Humidity (%)

Figure 4: Operating Conditions

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-020D with peak

temperatures at 260°C during up to 40sec including Pb-

free assembly in IR/Convection reflow ovens.

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.

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.

7 233°C = 451°F, 260°C = 500°F, 350°C = 662°F

IMPORTANT: After soldering the devices should be stored

at >75%RH for at least 12h to allow the polymer to re-

hydrate. Otherwise the sensor may read an offset that

slowly disappears if exposed to ambient conditions.

Alternatively the re-hydration process may be performed at

ambient conditions (>40%RH) during more than 5 days.

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

or condensed water (i.e. environments with high relative

humidity) the soldering pads shall be sealed (e.g.

conformal coating) 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.

Figure 6: Rear side electrodes of sensor, view from top side.

Figure 7: Recommended footprint for SHT1x. Values in mm.

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

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

1

.27

1.97

0.80

1.38

2.47

1.07

Ø0.60

1.27

7.47

0.8

3.48

0.47

4.61

1.27

1.8

7.08

No copper in this field

1.27

7.50

Temperature

Time

tP

T

P

T

L

T

S

(max)

tL

preheating

critical zone

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 4/11

following conditions: Temperature shall be in the range of

10°C – 50°C (0 – 125°C for limited time) and humidity at

20 – 60%RH (sensors that are not stored in ESD bags).

For sensors that have been removed from the original

packaging we recommend to store them in ESD bags

made of metal-in PE-HD8.

In manufacturing and transport the sensors shall be

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:

Baking: 100 – 105°C at < 5%RH for 10h

Re-Hydration: 20 – 30°C at ~ 75%RH for 12h 9.

1.5 Temperature Effects

Relative humidity reading strongly depends on

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 8: Top view of example of mounted SHT1x with slits

milled into PCB to minimize heat transfer.

8 For example, 3M antistatic bag, product “1910” with zipper .

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

Furthermore, there are self-heating effects in case the

measurement frequency is too high. Please refer to

Section 3.3 for detailed information.

1.6 Light

The SHT1x is not light sensitive. Prolonged direct

exposure to sunshine or strong UV radiation may age the

housing.

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.

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

(Delrin), PTFE (Teflon), PE, PEEK, PP, PB, PPS, PSU,

PVDF, PVF.

For sealing and gluing (use sparingly): Use 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 >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

proximity (e.g. in wires) for more than 10cm may result in

cross talk and loss of communication. This may be

A5Z

11

housing

PCB

o-ring

Melted plastic pin

SHT1x

membrane

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 5/11

resolved by routing VDD and/or GND between the two

data signals and/or using shielded cables. Furthermore,

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.

Capacitor should be placed as close to the sensor as

possible. Please see the Application Note “ESD, Latch-up

and EMC” for more information.

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 Tamb = 80°C according to JEDEC78A. See

Application Note “ESD, Latch-up and EMC” for more

information.

2 Interface Specifications

Name Comment

1 GND Ground

2 DATA Serial Data, bidirectional

3 SCK Serial Clock, input only

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.

Figure 10: Typical application circuit, including pull up resistor

RP and decoupling of VDD and GND by a capacitor.

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.

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)

and must remain stable while SCK is high. After the falling

edge of SCK the DATA value 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

required to pull the signal high – it should be noted that

pull-up resistors may be included in I/O circuits of

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.

Parameter Conditions min typ max Units

Power supply DC10 2.4 3.3 5.5 V

measuring 0.55 1 mA

average11 2 28 µA

Supply current sleep 0.3 1.5 µA

Low level output

voltage IOL < 4 mA 0 250 mV

High level output

voltage RP < 25 kΩ 90% 100%

VDD

Low level input

voltage Negative going

0% 20% VDD

High level input

voltage Positive going 80% 100%

VDD

Input current on pads

1 µA

on 4 mA

Output current Tri-stated (off) 10 20 µA

Table 2: SHT1x DC characteristics. RP stands for pull up

resistor, while IOL is low level output current.

10 Recommended voltage supply for highest accuracy is 3.3V, due to sensor

calibration.

11 Minimum value with one measurement of 8bit resolution without OTP reload

per second. Typical value with one measurement of 12bit resolution per

second.

A5Z

11

N

C

NC

1

2

3

4

Micro-

Controller

(Master)

GND

2.4

–

5.5V

DATA

SCK

VDD

R

P

VDD

GND

SHT1x

(Slave)

A5Z

11

100nF

10

k

Ω

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 6/11

Absolute maximum ratings for VDD versus GND are +7V

and -0.3V. Exposure to absolute maximum rating

conditions for extended periods may affect the sensor

reliability (e.g. hot carrier degradation, oxide breakdown).

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.

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. Note that DATA valid

read time is triggered by falling edge of anterior toggle.

Parameter Conditions min typ max

Units

VDD > 4.5V

0 0.1 5 MHz

FSCK SCK Frequency VDD < 4.5V

0 0.1 1 MHz

TSCKx

SCK hi/low time 100

ns

TR/TF

SCK rise/fall time 1 200

* ns

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

* TR_max + TF_max = (FSCK)-1 – TSCKH – TSCKL

** TR0 is determined by the RP*Cbus time-constant at DATA line

*** TV_max and TSU_max depend on external pull-up resistor (RP) and total bus

line capacitance (Cbus) at DATA line

**** TH0_max < TV – max (TR0, TF0)

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.

Figure 12: "Transmission Start" sequence

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

status register to default values. Wait minimum

11 ms before next command

11110

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).

DATA valid

read

DATA valid write

DATA

SCK

8

0%

2

0%

8

0%

2

0%

T

V

T

SCKL

T

SU

T

HO

T

SCK

T

SCKH

T

R

T

F

T

RO

T

FO

DATA

SCK

8

0%

2

0%

8

0%

2

0%

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 7/11

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.

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.

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.

Figure 13: Connection Reset Sequence

3.5 CRC 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 Checksum” for information

on how to calculate the CRC.

3.6 Status Register

Some of the advanced functions of the SHT1x such as

selecting measurement resolution, end-of-battery notice,

use of OTP reload or using the heater may be activated by

sending a command to the status register. The following

section gives a brief overview of these features.

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 Figure 14 and Figure 15 – the

assignation of the bits is displayed in Table 5.

0

1

0

Status Register

TS

ACK

Bit 7

ACK

Figure 14: Status Register Write

Figure 15: Status Register Read

Examples of full communication cycle are displayed in

Figure 16 and Figure 17.

0

Command 0

0

MSB

TS

Wait for

DATA ready

ACK

LSB Checksum

LSb

ACK

Figure 16: Overview of Measurement Sequence. TS = Trans-

mission Start, MSB = Most Significant Byte, LSB = Last

Significant Byte, LSb = Last Significant Bit.

Figure 17: Example RH measurement sequence for value “0000’0100“0011’0001” = 1073 = 35.50%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.

0

1

Status Register Checksum

TS

ACK

Bit 7

ACK

Bit 7

ACK

DATA

SCK

8

0%

2

0%

8

0%

2

0%

1

2

3

2

4 - 8

9

Transmission Start

DATA

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

Measurement

(80ms for 12bit)

Sleep

(wait for next

measurement)

Idle Bits

Skip ACK to end trans

mission

(if

no CR

C is used)

Sensor pulls DATA line low after

completion of measurement

MSb

LSb

MSb

LSb

15

14

13

12

11

10

9

8

ACK

7

6

5

4

3

2

1

0

A2

A1

A0

C4

C3

C2

C1

C0

ACK

7

6

5

4

3

2

1

0

ACK

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 8/11

Bit Type Description Default

7 reserved 0

6 R End of Battery (low voltage

detection)

‘0’ for VDD > 2.47

‘1’ for VDD < 2.47

X No default value,

bit is only updated

after a

measurement

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 ’1’ = 8bit RH / 12bit Temp.

resolution

’0’ = 12bit RH / 14bit Temp.

resolution

0 12bit RH

14bit Temp.

Table 5: Status Register Bits

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.

End of Battery function detects and notifies VDD voltages

below 2.47V. Accuracy is 0.05V.

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

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.

OTP reload: With this operation the calibration data is

uploaded to the register before each measurement. This

may be deactivated for reducing measurement time by

about 10ms.

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

12 Corresponds to 9 – 18°F

(SORH) with the following formula with coefficients given in

Table 6:

2

RH3RH21linear SOcSOccRH  (%RH)

SORH c1 c2 c3

12 bit -2.0468 0.0367 -1.5955E-6

8 bit -2.0468 0.5872 -4.0845E-4

Table 6: V4 humidity conversion coefficients

The values given in Table 6 are optimized coefficients for

V4 sensors. The parameter set for V3 sensors, which has

been proposed in earlier datasheets, still applies and is

provided by Sensirion upon request.

Values higher than 99% RH indicate fully saturated air and

must be processed and displayed as 100%RH13. Please

note that the humidity sensor has no significant voltage

dependency.

0%

20%

40%

60%

80%

100%

0 500 1000 1500 2000 2500 3000 3500

SORH sensor readout (12bit)

Relative Humidity

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 temperature compensation.

The temperature correction corresponds roughly to

0.12%RH/°C @ 50%RH. Coefficients for the temperature

compensation are given in Table 7.









linearRH21Ctrue RHSOtt25TRH  

SORH t1 t2

12 bit 0.01 0.00008

8 bit 0.01 0.00128

Table 7: Temperature compensation coefficients14

4.3 Temperature

The band-gap PTAT (Proportional To Absolute

Temperature) temperature sensor is very linear by design.

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.

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 9/11

Use the following formula to convert digital readout (SOT)

to temperature value, with coefficients given in Table 8:

T21 SOddT 

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 8: Temperature conversion coefficients15.

4.4 Dew Point

SHT1x is not measuring dew point directly, however dew

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 9:

 

TT Tm

100%

RH

lnm

TT Tm

100%

RH

ln

TTRH,T

n

nd









































Temperature Range Tn (°C) m

Above water, 0 – 50°C 243.12 17.62

Above ice, -40 – 0°C 272.62 22.46

Table 9: 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 “Introduction to Humidity”.

5 Environmental Stability

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

15 Temperature coefficients have slightly been adjusted compared to datasheet

SHTxx version 3.01. Coefficients apply to V3 as well as V4 sensors.

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 AEC-

Q100 Rev. G qualification test method. Sensor

specifications are tested to prevail under the AEC-Q100

temperature grade 2 test conditions listed in Table 1016.

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.

Environment Standard Results17

HTSL 125°C, 1000 hours Within

specifications

TC -50°C - 125°C, 1000 cycles

Acc. JESD22-A104-C Within

specifications

UHST 130°C / 85%RH / ≈2.3bar,

96h Within

specifications

THU 85°C / 85%RH, 1000h Within

specifications

ESD immunity MIL STD 883E, method 3015

(Human Body Model at ±2kV) Qualified

Latch-up force current of ±100mA with

Tamb = 80°C, acc. JEDEC 17 Qualified

Table 10: Qualification tests: HTSL = High Temperature Storage

Lifetime, TC = Temperature Cycles, UHST = Unbiased Highly

accelerated Stress Test, THB = Temperature Humidity Unbiased

6 Packaging

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 Pb, Cd,

Hg, Cr(6+), PBB and PBDE.

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.

6.2 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,

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.

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 10/11

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.

Figure 19: First label on reel: XX = Sensor Type (11 for SHT11),

NN = Chip Version (04 for V4), Y = last digit of year, RRR =

number of sensors on reel divided by 10 (200 for 2000 units),

TTTTT = Traceability Code.

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.

6.3 Shipping Package

SHT1x are shipped in 12mm tape at 100pcs, 400pcs and

2000pcs – for details see Figure 21 and Table 11. Reels

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

Tape & Reel 400 1-100098-04

SHT11 Tape & Reel 2000 1-100524-04

Tape & Reel 100 1-100085-04

SHT15 Tape & Reel 400 1-100093-04

Table 11: Packaging types per sensor type.

Dimensions of packaging tape are 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 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).

Device Type: 1-100PPP-NN

Description: Humidity & Temperature Sensor

SHTxx

Part Order No. 1-100PPP-NN or Customer Number

Date of Delivery: DD.MM.YYYY

Order Code: 46CCCC / 0

Lot No.: XX0-NN-YRRRTTTTT

Quantity: RRRR

RoHS: Compliant

Lot No.

2.00 ± 0.05

12.00

Ø1.50 MIN

1

.00

1.75

± 0.

10

5.50

± 0.

05

12.0

± 0.

3

R0.5 TYP

8.20

2.80

0.30

± 0.05

R0.3 MAX

5.80

A5Z

11

Datasheet SHT1x

www.sensirion.com Version 4.3 – May 2010 11/11

Revision History

Date Version Page(s) Changes

July 2008 4.0 1 – 11 New release, rework of datasheet

September 2008 4.1 3, 4 Adjustment of normal operating range and recommendation for antistatic bag

April 2009 4.2 2, 7 Amended foot note 2, communication diagram updated (Figure 17).

May 2010 4.3 1 – 11 Various errors corrected and additional information given (ask for change protocol).

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.

CMOSens® is a trademark of Sensirion

Headquarter and Sales Offices

Headquarter

SENSIRION AG Phone: +41 44 306 40 00

Laubisruetistr. 50 Fax: +41 44 306 40 30

CH-8712 Staefa ZH info@sensirion.com

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SENSIRION Inc. Phone: +1 805 409 4900

2801 Townsgate Rd., Suite 204 Fax: +1 805 435 0467

Westlake Village, CA 91361 michael.karst@sensirion.com

USA http://www.sensirion.com/

Sales Office Japan:

SENSIRION JAPAN Co. Ltd. Phone: +81 3 3444 4940

Postal Code: 108-0074 Fax: +81 3 3444 4939

Shinagawa Station Bldg. 7F, info@sensirion.co.jp

4-23-5, Takanawa, Minato-ku http://www.sensirion.co.jp

Tokyo, Japan

Sales Office Korea:

SENSIRION KOREA Co. Ltd. Phone: +82 31 440 9925~27

#1414, Anyang Construction Tower B/D, Fax: +82 31 440 9927

1112-1, Bisan-dong, Anyang-city info@sensirion.co.kr

Gyeonggi-Province http://www.sensirion.co.kr

South Korea

Sales Office China:

Sensirion China Co. Ltd. phone: +86 755 8252 1501

Room 2411, Main Tower fax: +86 755 8252 1580

Jin Zhong Huan Business Building, info@sensirion.com.cn

Futian District, Shenzhen, www.sensirion.com.cn

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PR China

Find your local representative at: http://www.sensirion.com/reps