SHT21S Datasheet by Sensirion AG

3.0 2.4 max Bottom NC NC info@sensirion.com. SENSIRION rue sensun (OMPANY wfpéﬁ'ﬁ nd an as Applicaﬁon No1es is www.sensirion.com/sh121.

www.sensirion.com Version 4 – May 2014 1/10

Datasheet SHT21S

Humidity and Temperature Sensor IC

 Fully calibrated

 SDM interface convertible to analog output

 Low power consumption

 Excellent long term stability

 DFN type package – reflow solderable

Dimensions

Figure 1: Drawing of SHT21S sensor package, dimensions

are given in mm (1mm = 0.039inch), tolerances are ±0.1mm.

The die pad (center pad) is internally connected to VSS. The NC

pads must be left floating. Numbering of E/O pads starts at lower

right corner (indicated by notch in die pad) and goes clockwise

(compare Table 2).

Sensor Chip

SHT21S feature a generation 4C CMOSens® chip.

Besides the capacitive relative humidity sensor and the

band gap temperature sensor, the chip contains an

amplifier, A/D converter, OTP memory and a digital

processing unit.

Material Contents

While the sensor itself is made of Silicon the sensors’

housing consists of a plated Cu lead-frame and green

epoxy-based mold compound. The device is fully RoHS

and WEEE compliant, e.g. free of Pb, Cd and Hg.

Additional Information

Additional information such as Application Notes is

available from the web page www.sensirion.com/sht21.

For more information please contact Sensirion via

info@sensirion.com.

1.0

2.4

0.3

0.4

1.5

0.4

0.75

1.1

0.2

SCL

SDA

NC

VSS

VDD

Bottom

View

SHT21

D0AC4

3.0

2.2

1.4 max

3.0

0.3 typ

2.4 max

Product Summary

The SHT21 humidity and temperature sensor of Sensirion

has become an industry standard in terms of form factor

and intelligence: Embedded in a reflow solderable Dual

Flat No leads (DFN) package of 3 x 3mm foot print and

1.1mm height it provides calibrated, linearized sensor

signals in analog Sigma Delta Modulated (SDM) format.

The SHT2x sensors contain a capacitive type humidity

sensor, a band gap temperature sensor and specialized

analog and digital integrated circuit – all on a single

CMOSens® chip. This yields in an unmatched sensor

performance in terms of accuracy and stability as well as

minimal power consumption.

SDM signal is a pulse sequence that with a low pass filter

may be converted into analog voltage output. The data

signal is provided on SDA line. Pulling SCL high or low

allows for switching between humidity and temperature,

respectively. The sensor measures the physical values

twice per second.

Every sensor is individually calibrated and tested. Lot

identification is printed on the sensor.

With this set of features and the proven reliability and

long-term stability, the SHT2x sensors offer an

outstanding performance-to-price ratio. For testing SHT2x

two evaluation kits EK-H4 and EK-H5 are available.

SENSIRION was sensor: (DMFANV Parameter Condition Value Units Parameter Condition Value Units Resolution 12 bit 0.04 %RH Resolution 14 bit 0.01 ”C : t max see Figure 2 %RH max see Figure 3 ”C : t 1 Operating Range extended -40 to 125 ”C Nonlinearily <0 1="" %rh="" r="" 1="" long="" term="" drift="" typ.="">< 0.02="" ”c/yr="" operating="" range="" extended="" 0="" to="" 100="" %rh="" long="" term="" drift="" 1="" typ.="">< 0="" 25="" %rh/yr="" parameter="" condition="" min="" typ="" max="" units="" supply="" voltage.="" vdd="" 2.1="" 3.0="" 3.6="" v="" supply="" current.="" dd="" 160="" pa="" power="" dissipation="" 0="" 45="" mw="" measurement="" swttch="" rh/t="" on="" sda="" $01.="" up="" 9="" rh;="" scl="" down="" —)="" t="" sensor="" type="" packaging="" quantity="" order="" number="" tape="" &="" reel="" 400="" 1-100718—01="" tape="" &="" reel="" 1500="" 1-100697—01="" tape="" &="" reel="" 5000="" 1-100696—01="">

www.sensirion.com Version 4 – May 2014 2/10

Sensor Performance

Relative Humidity

123

Parameter

Condition

Value

Units

Resolution

12 bit

0.04

%RH

Accuracy

tolerance 1

typ

2.0

%RH

max

see Figure 2

%RH

Repeatability

0.1

%RH

Hysteresis

1

%RH

Nonlinearity

<0.1

%RH

Response time 2

 63%

8

s

Operating Range

extended 3

0 to 100

%RH

Long Term Drift 4

Typ.

< 0.25

%RH/yr

Figure 2 Typical and maximal tolerance at 25°C for relative

humidity. For extensive information see Users Guide, Sect. 1.2.

For electronic impacts on accuracy please consult Sect. 5.3.

Electrical Specification

Parameter

Condition

min

typ

max

Units

Supply Voltage, VDD

2.1

3.0

3.6

V

Supply Current, IDD 5

160

µA

Power Dissipation 5

0.48

mW

Measurement

Frequency

2

Hz

Switch RH/T on SDA

SCL up  RH; SCL down  T

Table 1 Electrical specification. For absolute maximum

values see Chapter 4.1 of Users Guide.

1

Accuracies are tested at Outgoing Quality Control at 25°C and 3.0V. Values

exclude hysteresis and long term drift and are applicable to non-condensing

environments only.

2

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

3

Normal operating range: 0-80%RH, beyond this limit sensor may read a

reversible offset with slow kinetics (+3%RH after 60h at humidity >80%RH). For

more details please see Section 1.1 of the Users Guide.

Temperature

456

Parameter

Condition

Value

Units

Resolution

14 bit

0.01

°C

Accuracy

tolerance 1

typ

0.3

°C

max

see Figure 3

°C

Repeatability

0.1

°C

Operating Range

extended 3

-40 to 125

°C

Response Time 6

 63%

5 to 30

s

Long Term Drift 7

Typ.

< 0.02

°C/yr

Figure 3 Typical and maximal temperature accuracy tolerance.

For electronic impacts on accuracy please consult Sect. 5.3.

Packaging Information

Sensor Type

Packaging

Quantity

Order Number

SHT21S

Tape & Reel

400

1-100718-01

Tape & Reel

1500

1-100697-01

Tape & Reel

5000

1-100696-01

This datasheet is subject to change and may be amended

without prior notice.

4

Typical value for operation in normal RH/T operating range. Max. value is < 0.5

%RH/y. Value may be higher in environments with vaporized solvents, out-

gassing tapes, adhesives, packaging materials, etc. For more details please

refer to Handling Instructions.

5

Values of Supply Current and Power Dissipation are based upon fixed VDD =

3.0V and T = 25°C applying a low pass filter as proposed in Sect. 5.3.

6

Response time depends on heat conductivity of sensor substrate.

7

Max. value is < 0.04°C/y.

± 0

± 2

± 4

± 6

± 8

± 10

010 20 30 40 50 60 70 80 90 100

ΔRH(%RH)

Relative Humidity (%RH)

maximum accuracy

typical accuracy

± 0.0

± 0.5

± 1.0

± 1.5

± 2.0

-40 -20 0 20 40 60 80 100 120

ΔT (C)

Temperature (°C)

maximum accuracy

typical accuracy

SENSIRION THE ssuson (owns/u" 010 20 30 40 50 60 70 80 Figure 6 Typical accuracy of re‘ative humidwty measuremen

www.sensirion.com Version 4 – May 2014 3/10

Users Guide SHT21S

1 Extended Specification

For details on how Sensirion is specifying and testing

accuracy performance please consult Application Note

“Statement on Sensor Specification”.

1.1 Operating Range

The sensor works stable within recommended Normal

Range – see Figure 4. Long term exposure to conditions

outside Normal Range, especially at humidity >80%RH,

may temporarily offset the RH signal (+3%RH after 60h).

After return into the Normal Range it will slowly return

towards calibration state by itself. Prolonged exposure to

extreme conditions may accelerate ageing.

Figure 4 Operating Conditions

1.2 RH accuracy at various temperatures

Typical RH accuracy at 25°C is defined in Figure 2. For

other temperatures, typical accuracy has been evaluated

to be as displayed in Figure 5.

Figure 6 Typical accuracy of relative humidity measurements

given in %RH for temperatures 0 – 80°C.

2 Application Information

2.1 Soldering Instructions

The DFN’s die pad (centre pad) and perimeter I/O pads

are fabricated from a planar copper lead-frame by over-

molding leaving the die pad and I/O pads exposed for

mechanical and electrical connection. Both the I/O pads

and die pad should be soldered to the PCB. In order to

prevent oxidation and optimize soldering, the bottom side

of the sensor pads is plated with Ni/Pd/Au.

On the PCB the I/O lands

8

should be 0.2mm longer than

the package I/O pads. Inward corners may be rounded to

match the I/O pad shape. The I/O land width should match

the DFN-package I/O-pads width 1:1 and the land for the

die pad should match 1:1 with the DFN package – see

Figure 7.

The solder mask

9

design for the land pattern preferably is

of type Non-Solder Mask Defined (NSMD) with solder

mask openings larger than metal pads. For NSMD pads,

the solder mask opening should be about 120μm to

150μm larger than the pad size, providing a 60μm to 75μm

design clearance between the copper pad and solder

mask. Rounded portions of package pads should have a

matching rounded solder mask-opening shape to minimize

the risk of solder bridging. For the actual pad dimensions,

each pad on the PCB should have its own solder mask

opening with a web of solder mask between adjacent

pads.

Figure 7 Recommended metal land pattern for SHT2x. Values

in mm. Die pad (centre pad) may be left floating or be connected

to ground, NC pads shall be left floating. The outer dotted line

represents the outer dimension of the DFN package.

For solder paste printing a laser-cut, stainless steel stencil

with electro-polished trapezoidal walls and with 0.125mm

stencil thickness is recommended. For the I/O pads the

stencil apertures should be 0.1mm longer than PCB pads

8

The land pattern is understood to be the metal layer on the PCB, onto which

the DFN pads are soldered to.

9

The solder mask is understood to be the insulating layer on top of the PCB

covering the connecting lines.

100 ±3.5 ±3 ±3 ±3 ±3 ±3 ±3.5 ±4 ±4

90 ±3.5 ±3 ±2.5 ±2.5 ±2.5 ±2.5 ±3 ±3.5 ±4

80 ±3 ±2.5 ±2 ±2 ±2 ±2.5 ±2.5 ±3 ±3.5

70 ±3 ±2.5 ±2 ±2 ±2 ±2 ±2.5 ±2.5 ±3

60 ±2.5 ±2 ±2 ±2 ±2 ±2 ±2 ±2.5 ±2.5

50 ±2.5 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2.5

40 ±2.5 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2

30 ±2.5 ±2 ±2 ±2 ±2 ±2 ±2 ±2 ±2

20 ±2.5 ±2.5 ±2 ±2 ±2 ±2 ±2 ±2 ±2

10 ±3 ±3 ±2.5 ±2.5 ±2.5 ±2.5 ±2.5 ±2.5 ±2.5

0 ±3.5 ±3.5 ±3 ±3 ±3 ±3 ±3 ±3 ±3

010 20 30 40 50 60 70 80

Relative Humidity [%RH]

Temperature [°C]

0

10

20

30

40

50

60

70

80

90

100

-40 -20 0 20 40 60 80 100 120

Relative Humidity (%)

Temperature (°C)

Max.

Range

Normal

Range

1.0

0.3

0.4

1.5

0.4

0.7

0.2

2.4

T (max) preheating «mum mne~>l Time SENSIRION was sense»: COMPANY

Datasheet SHT21S

www.sensirion.com Version 4 – May 2014 4/10

and positioned with 0.1mm offset away from the centre of

the package. The die pad aperture should cover about 70

– 90% of the pad area – say up to 1.4mm x 2.3mm

centered on the thermal land area. It can also be split in

two openings.

Due to the low mounted height of the DFN, “no clean”

type 3 solder paste

10

is recommended as well as Nitrogen

purge during reflow.

Figure 8 Soldering profile according to JEDEC standard. TP <=

260°C and tP < 30sec for Pb-free assembly. TL < 220°C and tL <

150sec. Ramp-up/down speeds shall be < 5°C/sec.

It is important to note that the diced edge or side faces of

the I/O pads may oxidise over time, therefore a solder fillet

may or may not form. Hence there is no guarantee for

solder joint fillet heights of any kind.

For soldering SHT2x, standard reflow soldering ovens may

be used. The sensor is qualified to withstand soldering

profile according to IPC/JEDEC J-STD-020 with peak

temperatures at 260°C during up to 30sec for Pb-free

assembly in IR/Convection reflow ovens (see Figure 8).

For manual soldering contact time must be limited to 5

seconds at up to 350°C.

Immediately after the exposure to high temperatures the

sensor may temporarily read a negative humidity offset

(typ. -1 to -2 %RH after reflow soldering). This offset

slowly disappears again by itself when the sensor is

exposed to ambient conditions (typ. within 1-3 days). If RH

testing is performed immediately after reflow soldering,

this offset should be considered when defining the test

limits.

In no case, neither after manual nor reflow soldering, a

board wash shall be applied. Therefore, and as mentioned

above, it is strongly recommended to use “no-clean” solder

paste. In case of applications 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.

10

Solder types are related to the solder particle size in the paste: Type 3 covers

the size range of 25 – 45 µm (powder type 42).

2.2 Storage Conditions and Handling Instructions

Moisture Sensitivity Level (MSL) is 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.

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 this reason 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

10°C – 50°C 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-HD

11

.

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.

2.3 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 sensor 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 sensor and the

rest of the PCB or milling a slit into the PCB around the

sensor – see Figure 9.

Due to the possible high frequency output the sensor may

heat up if long cables are applied. Therefore, a low pass

filter shall be placed close to the sensor. Please compare

Section 5.3 for further information.

11

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

Temperature

Time

tP

TP

TL

TS (max)

tL

preheating

critical zone

SENSIRION THE senses COMPANY Pin Name Comment 1 SDA Data bit-stream 2 VSS Ground 4 3 5 VDD Supply Voltage 5 2 6 SCL Setector for RH or T 6 ‘ 3,4 NC Nat connected VDD Seted RH NT 1 3 AWOL SDM bi| stream SDA

Datasheet SHT21S

www.sensirion.com Version 4 – May 2014 5/10

Figure 9 Top view of example of mounted SHT2x with slits

milled into PCB to minimize heat transfer.

2.4 Light

The SHT2x is not light sensitive. Prolonged direct

exposure to sunshine or strong UV radiation may age the

sensor.

2.5 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), 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 sensor (see Section 2.2). 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.

3 Interface Specifications

Name

Comment

1

SDA

Data bit-stream

2

VSS

Ground

5

VDD

Supply Voltage

6

SCL

Selector for RH or T

3,4

NC

Not connected

Table 2 SHT21S pin assignment (top view)

3.1 Power Pins (VDD, VSS)

The supply voltage of SHT21S must be in the range of 2.1

– 3.6V, recommended supply voltage is 3.0V. Power

supply pins Supply Voltage (VDD) and Ground (VSS) must

be decoupled with a 100nF capacitor, that shall be placed

as close to the sensor as possible – see Figure 10.

3.2 SCL – Output Selector Pad

SCL is used to select humidity or temperature output. SCL

high yields humidity output, SCL low yields temperature

output.

Figure 10 Typical application circuit, including decoupling of

VDD and VSS by a capacitor.

3.3 SDA – Bit Stream Pad

On SDA the sensor is providing SDM output. The signal is

carrying humidity or temperature data depending on SCL

being high or low, respectively. See Table 4 for detailed

I/O characteristic of the sensor.

4 Electrical Characteristics

4.1 Absolute Maximum Ratings

The electrical characteristics of SHT21S are defined in

Table 1. The absolute maximum ratings as given in Table

3 are stress ratings only and give additional information.

Functional operation of the device at these conditions is

not implied. Exposure to absolute maximum rating

conditions for extended periods may affect the sensor

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

SDA

SCL

VSS

VDD

C = 100nF

SHT2x

SDM bit stream

Select RH or T

1

6

5

2

4

3

Parameter min max Units VDD 10 V85 -0.3 5 V Digirar I/O Pms (SDA, SCL) Input Current on any Fin 400 100 mA Outpul Low Voltage, VOL 0 V Outpul High Vollage, VOH VDD V Outpul Srnk Current, IOL 40 “A SENSIRION was sensor: COMPANY SDA ' DD 0V VDD Se‘ec‘ RH orT a \ Mm

Datasheet SHT21S

www.sensirion.com Version 4 – May 2014 6/10

Parameter

min

max

Units

VDD to VSS

-0.3

5

V

Digital I/O Pins (SDA, SCL)

to VSS

-0.3

VDD + 0.3

V

Input Current on any Pin

-100

100

mA

Table 3 Electrical absolute maximum ratings

ESD immunity is qualified according to JEDEC JESD22-

A114 method (Human Body Model at 4kV), JEDEC

JESD22-A115 method (Machine Model 200V) and ESDA

ESD-STM5.3.1-1999 and AEC-Q100-011 (Charged

Device Model, 750V corner pins, 500V other pins). Latch-

up immunity is provided at a force current of 100mA with

Tamb = 125°C according to JEDEC JESD78. For exposure

beyond named limits the sensor needs additional

protection circuit.

4.2 Input / Output Characteristics

The electrical characteristics such as power consumption,

low and high level input and output voltages depend on

the supply voltage. For proper communication with the

sensor it is essential to make sure that signal design is

strictly within the limits given in Table 4.

Parameter

min

typ

max

Units

Output Low Voltage, VOL

0

V

Output High Voltage, VOH

VDD

V

Output Sink Current, IOL

40

µA

Table 4 DC characteristics of input / output pad. VDD = 2.1 V to

3.6 V, T = -40 °C to 125 °C, unless otherwise noted.

5 Communication with Sensor

5.1 Start up Sensor

As a first step, the sensor is powered up to the chosen

supply voltage VDD (between 2.1V and 3.6V). After

power-up, the sensor needs at most 150ms for reaching

idle state. During that time SDA is in undefined state. Then

the sensor starts measuring and providing data on SDM

bit-stream.

5.2 SDM Output Principle

Sigma Delta Modulation is a bit-stream of pulses; the more

high pulses the higher the value in the full measurement

range – see Figure 11. Such information is humidity for

SCL pulled high and temperature for SCL pulled low. The

fundamental frequency of SDM is in the range of roughly 4

kHz and 65 kHz.

Figure 11 Schematic principle of SDM signal. X represents

either RH or T at different levels of sensor output.

5.3 Converting SDM to Analog Signal

An SDM signal normally is converted to an analog voltage

signal by the addition of a low-pass filter. Figure 12

displays a typical circuit where a simple RC-filter is used.

For conversion into physical values please read the

following Chapter.

Figure 12 Typical circuit with low pass filter (surrounded by

hatched line) for analog output. Recommended component size:

RLP = 100kΩ and CLP = 220nF. By pulling SCL low or high, the

output value is switched to temperature or humidity,

respectively.

For an acceptable small ripple of the analog voltage

signal, a cut-off frequency of 7Hz is recommended. Typical

values for the low pass filter components are R = 100kΩ

and C = 220nF. The corresponding ripple of the signal is

limited to maximal amplitude of ±0.2%RH and ±0.28°C,

respectively. If larger deviations are acceptable the

capacitor size can be reduced.

Important: The maximum current from SDA should not

exceed 40µA. Therefore, there are restrictions on the size

of the resistance RLP. Furthermore, the current should be

kept as low as possible and therefore the input impedance

of the reading buffer shall be larger than 50MΩ (60nA

input biased current). Eventually, cable length between

sensor and low pass filter shall be kept as short as

possible in order to prevent self heating.

Please note, that ripples and impacts by impedance are

not considered in the accuracy statement.

SDA

VDD

0V

SDA

VDD

0V

SDA

VDD

0V

X ≈ 10%

X ≈ 50%

X ≈ 90%

SDA

SCL

VSS

VDD

C = 100nF

SHT21S

VSO

Select RH or T

RLP

CLP

SENSIRION rue sensor: COMPANY Environment Standard Results HTOL 125°C, 408 hours Pass TC ~50°C - 125°C, 1000 cycles Pass UHST 130°C / 85%RH / =2.3bar, 96h Pass THB 85°C / 85%RH, 1000h Pass HTSL 150°C, 1000h Pass ELFR 125°C, 45h Pass ESD 1mmunity 1 1 Pass Lalch-up force current of t100mA wilh T Pass

Datasheet SHT21S

www.sensirion.com Version 4 – May 2014 7/10

6 Conversion of Signal Output

After the low pass filter the sensor provides an output

Voltage VSO which as a portion of VDD then is converted

into a physical value.

Resolution is set to 10 bit for relative humidity and 12 bit

for temperature and cannot be changed. The sensor

reading is linearized and hence it can be converted to a

physical value by an easy linear equation.

6.1 Relative Humidity Conversion

With the relative humidity signal output the relative

humidity RH is obtained by the following formula (result in

%RH):

VDD

V

125+-6=RH SO



The physical value RH given above corresponds to the

relative humidity above liquid water according to World

Meteorological Organization (WMO). For relative humidity

above ice RHi the values need to be transformed from

relative humidity above water RHw at a certain temperature

t. The equation is given in the following, compare also

Application Note “Introduction to Humidity”:

































 tλ

tβ

exp

tλ

tβ

expRHRH

i

w

wi

Units are %RH for relative humidity and °C for

temperature. The corresponding coefficients are defined

as follows: βw = 17.62, λw = 243.12°C, βi = 22.46, λi =

272.62°C.

6.2 Temperature Conversion

The temperature T is calculated by inserting temperature

signal output ST into the following formula (result in °C):

VDD

V

175.7246.85T SO



7 Environmental Stability

The SHT2x sensor series were tested based on AEC-

Q100 Rev. G qualification test method where applicable.

Sensor specifications are tested to prevail under the AEC-

Q100 temperature grade 1 test conditions listed in Table

5

12

.

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

12

Sensor operation temperature range is -40 to 125°C (AEC-Q100 temperature

grade 1).

performance in the field or for customer’s specific

application.

Environment

Standard

Results13

HTOL

125°C, 408 hours

Pass

TC

-50°C - 125°C, 1000 cycles

Pass

UHST

130°C / 85%RH / ≈2.3bar, 96h

Pass

THB

85°C / 85%RH, 1000h

Pass

HTSL

150°C, 1000h

Pass

ELFR

125°C, 48h

Pass

ESD immunity

HBM 4kV, MM 200V, CDM

750V/500V (corner/other pins)

Pass

Latch-up

force current of ±100mA with Tamb

= 125°C

Pass

Table 5: Qualification tests: HTOL = High Temperature

Operating Lifetime, TC = Temperature Cycles, UHST =

Unbiased Highly accelerated Stress Test, THB = Temperature

Humidity Biased, HTSL = High Temperature Storage Lifetime,

ELFR = Early Life Failure Rate. For details on ESD see Sect.

4.1.

If sensors are qualified for reliability and behavior in

extreme conditions, 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”.

8 Packaging

8.1 Packaging type

SHT2x sensors are provided in DFN packaging (in

analogy with QFN packaging). DFN stands for Dual Flat

No leads.

The sensor chip is mounted to a lead frame made of Cu

and plated with Ni/Pd/Au. Chip and lead frame are over

molded by green epoxy-based mold compound. Please

note that side walls of sensors are diced and hence lead

frame at diced edge is not covered with respective

protective coating. The total weight of the sensor is 25mg.

8.2 Filter Cap and Sockets

For SHT2x a filter cap SF2 is available. It is designed for

fast response times and compact size. Please find the

datasheet on Sensirion’s web page.

13

According to accuracy and long term drift specification given on Page 2.

SENSIRION was sense»: COMPANY sensors ockets, number 10LQSO SENSIRION THE SENSOR COMPANY www.|ocknest.com

Datasheet SHT21S

www.sensirion.com Version 4 – May 2014 8/10

For testing of SHT2x sensors sockets, such as from

Plastronics, part number 10LQ50S13030 are

recommended (see e.g. www.locknest.com).

8.3 Traceability Information

All SHT2x are laser marked with an alphanumeric, five-

digit code on the sensor – see Figure 13.

Figure 13 Laser marking on sensor. For details see text.

The marking on the sensor consists of two lines with five

digits each. The first line denotes the sensor type

(SHT21). The first digit of the second line defines the

output mode (D = digital, Sensibus and I2C, P = PWM, S =

SDM). The second digit defines the manufacturing year (0

= 2010, 1 = 2011, etc.). The last three digits 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.

Reels are also labeled, as displayed in Figure 13 and

Figure 14, and give additional traceability information.

Figure 14: First label on reel: XX = Sensor Type (21 for SHT21),

O = Output mode (D = Digital, P = PWM, S = SDM), NN =

product revision no., Y = last digit of year, RRR = number of

sensors on reel divided by 10 (200 for 2000 units), TTTTT =

Traceability Code.

Figure 15: Second label on reel: For Device Type and Part

Order Number (See Packaging Information on page 2), Delivery

Date (also Date Code) is date of packaging of sensors (DD =

day, MM = month, YYYY = year), CCCC = Sensirion order

number.

8.4 Shipping Package

SHT2x are provided in tape & reel shipment packaging,

sealed into antistatic ESD bags. For SHT21S standard

packaging sizes are 400, 1500 and 5000 units per reel.

Each reel contains 440mm (55 pockets) header tape and

200mm (25 pockets) trailer tape.

The drawing of the packaging tapes with sensor

orientation is shown in Figure 16. The reels are provided in

sealed antistatic bags.

Figure 16 Sketch of packaging tape and sensor orientation.

Header tape is to the right and trailer tape to the left on this

sketch.

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: 45CCCC / 0

SHT21

S0AC4

Lot No.: XXO-NN-YRRRTTTTT

Quantity: RRRR

RoHS: Compliant

Lot No.

8.0

2.0

4.0

0.3

1.3

R0.3 MAX

R0.25

Ø1.5 MIN

3.3

0.25

3.3

1.75

5.5

12.0

SENSIRION was sensor: COMPANY Date Version Page(s) Changes 19 Aug 2009 0.6 1. 7 Figure 1, add delails to Chapler 7, add coefﬁcients lo Tables 5, 6. 4 March 2010 1.0 1 — 9 Complelely revised version. Require Change Protocol for details. 5 May 2010 1.1 1 — 9 Eliminalion of errors and addition of information (ask for change protocol) 27 April 2011 2 1 — 4, Updated lemperalure accuracy specificalions. MSL and slandards. Eliminalion of December 2011 3 1. 7 Minor lexl adaptations and corrections. May 2014 4 1—4, 7-8 Sensor window dimension updated, several minor adluslmenls

www.sensirion.com Version 4 – May 2014 9/10

Revision History

Date

Version

Page(s)

Changes

19 Aug 2009

0.6

1, 7

Figure 1, add details to Chapter 7, add coefficients to Tables 5, 6.

4 March 2010

1.0

1 – 9

Completely revised version. Require Change Protocol for details.

5 May 2010

1.1

1 – 9

Elimination of errors and addition of information (ask for change protocol)

27 April 2011

2

1 – 4,

6 – 10

Updated temperature accuracy specifications, MSL and standards. Elimination of

errors. For detailed information, please require complete change list at

info@sensirion.com.

December 2011

3

1, 7

Minor text adaptations and corrections.

May 2014

4

1-4, 7-8

Sensor window dimension updated, several minor adjustments

SENSIRION n45 sense»: COMPANY SENSIRION AG fax: +41 44 306 info@sensinon.com www.sensm0n.com Sensirion AG (Germany) info@sensinon.com www.sensm0n.com Sensiricn Inc , USA phone +1 805 409 49 mm us@sensin0n.com www.5ensirion com phone +81 3 3444 mfo@sensirion 0032 www.5ensirion 00 Q Sensinon Korea Co Ltd phone: +82 31 337 infc@sensxrion.co.kr www.5ensiricn.co.kr phone: +86 755 8252 infc@sensxrion.com cn www.5ensiricn.com.cn wwwsensmonmmlcomam

Datasheet SHT21S

www.sensirion.com Version 4 – May 2014 10/10

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

Headquarters and Subsidiaries

SENSIRION AG

Laubisruetistr. 50

CH-8712 Staefa ZH

Switzerland

phone: +41 44 306 40 00

fax: +41 44 306 40 30

info@sensirion.com

www.sensirion.com

Sensirion Inc., USA

phone: +1 805 409 4900

info_us@sensirion.com

www.sensirion.com

Sensirion Japan Co. Ltd.

phone: +81 3 3444 4940

info@sensirion.co.jp

www.sensirion.co.jp

Sensirion Korea Co. Ltd.

phone: +82 31 337 7700~3

info@sensirion.co.kr

www.sensirion.co.kr

Sensirion China Co. Ltd.

phone: +86 755 8252 1501

info@sensirion.com.cn

www.sensirion.com.cn

Sensirion AG (Germany)

phone: +41 44 927 11 66

info@sensirion.com

www.sensirion.com

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

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