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HTU31 RH/T SENSOR IC

Relative Humidity & Temperature Sensor

• HTU31D Digital RH/T Sensor

• HTU31V Analog RH/T Sensor

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TE CONNECTIVITY SENSORS /// HTU31 RH/T SENSOR IC

REV3 01/2021

te.com

HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Characteristics

• Fully calibrated, temperature compensated digital output

• High accuracy: ±2%RH and ±0.2°C

• Fast humidity response time: 5s

• Wide supply voltage range from 3V to 5.5V

• Low average current: 1µA typical

• Compact 6-Pin DFN package: 2.5x2.5x0.9mm

• Fast I²C Interface with 2 configurable addresses

• Fully RoHS and REACH compliant

Features

• High Reliability and Robustness

• Fast Recovery after Saturation

• Fully Compatible with Reflow Process

General Description

• Fully Interchangeable without

The HTU31 is one of the smallest and most accurate humidity sensors on

the market. TE Connectivity precision engineering and 20+ years of

experience in humidity and temperature combination sensors, enabled this

new product with fast response time, precision measurement, low

hysteresis, robustness to reflow assembly process and sustained

performance even when exposed to extreme temperature [-40° to 125°C]

and humidity [0%RH to 100%RH] environments.

Calibration

• Serial Individual Marking for Traceability

• Lead Free

• Low Power Consumption

Applications

HTU31 humidity & temperature sensor includes both digital (D) and analog

(V) versions and combines multiple functions with an application-friendly

operating supply voltage range from 3V to 5.5V.

• Home Appliance

• Medical

• Printers

HTU31 sensor is available in small and large volumes to meet the ever-

changing demands of our customers.

• Humidifiers

• Automotive

• Meteorology

• Environmental Monitoring & Trackers

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TE CONNECTIVITY SENSORS /// HTU31D RH/T SENSOR IC

REV3 01/2021

HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

PERFORMANCE SPECIFICATIONS

Relative Humidity Specifications

V

_dd= 5V 25°C

Characteristics

Condition

Max¹

Value

0 to 100

±2

Units

%RH

Notes / Conditions

Humidity Operating Range

Relative Humidity Accuracy

Typical

Figure 1 Humidity

Sensor Rating @25°C

Resolution

Typical

0.01

%RH

Table 11 Humidity and

Temperature

Conversion Parameters

Hysteresis

@25°C

τ_63%

±0.7

5

%RH

Response Time²

s

Recovery Time after Condensation³

Long Term Drift⁴

Typical

10

s

<0.25

%RH / year

Table 1 Humidity Specifications

Temperature Specifications

V_dd= 5V 25°C

Characteristics

Condition

Value

-40 to 125

±0.2

Units

°C

Notes / Conditions

Temperature Operating Range

Temperature Accuracy

Typical

°C

Figure 2 Temperature

Sensor Rating

Resolution

0.016

°C

Table 11 Humidity and

Temperature

Conversion Parameters

Response Time²

Long Term Drift

10

s

τ_63%

Typical

0.04

°C / year

Table 2 Temperature Specifications

¹Cf. Figure 3 Humidity and Temperature Operating Range

²With 1m.s^-1air flow

³Measured according to AFNOR standard NFX 15-113, with 3 m.s^-1air flow

⁴Typical application in regular environmental variation within optimum measurement range

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Humidity Sensor Rating

10

9

8

7

6

5

4

3

2

1

0

Maximal Tolerance

Typical Tolerance

0

10

20

30

40

50

60

70

80

90

100

Relative Humidity (%RH)

Figure 1 Humidity Sensor Rating @25°C

Temperature Sensor Rating

2

1.8

1.6

1.4

1.2

1

Maximal Tolerance

Typical Tolerance

0.8

0.6

0.4

0.2

0

-40

-20

0

20

40

60

80

100

120

Temperature (°C)

Figure 2 Temperature Sensor Rating

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

SENSOR INTEGRATION

Absolute Maximum Operating Conditions

Ratings

Symbol

Tstg

Vcc

Value

-40 to 150

Unit

Notes / Conditions

Storage Temperature⁵

Supply Voltage (Peak)

Humidity Operating Range

Temperature Operating Range

VDD to GND

°C

Vdc

%RH

°C

5.5

RH

0 to 100

Ta

-40 to +125

-0.3 to 5.5

V

Digital I/O pins (DATA/SCL) to GND

-0.3 to

V

VDD +0.3

ESD HBM (Human Body Model)⁶

ESD CDM (Charged Device Model)⁷

Latch Up Sensitivity⁸

±4

kV

V

750

±300

mA

Table 3 Maximum Operating Conditions

Figure 3 Humidity and Temperature Operating Range

The sensor should operate at peak condition less than 10% of the operating life. Exposure to absolute maximum

humidity/temperature conditions for extended periods may temporarily induce an offset on RH measurement (+5%RH above

accuracy specifications, which will recover over time) and accelerate its ageing.

⁵Sensor in specifications after 1000h storage @150°C

⁶According to ANSI/ESDA/JEDEC JS-001-2017, AEC-Q100-002.

⁷According to JESD22-C101, AEC-Q100-011

⁸According to JESD78

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Electrical Specifications

V_dd= 5V 25°C

Characteristics

Supply Voltage

Symbol

Min

Typ

5.0

Max

5.5

Unit

V

Notes / Conditions

V_dd

i_dd

3.0

0.13

1.04

414

0.65

5.20

2.07

2.0

0.40

µA

Sleep mode

Typical⁹

Current Consumption

µA

Peak / Measuring mode

Sleep mode

Typical

2.00

µW

mW

kΩ

Power Dissipation

Heater

Peak / Measuring mode

2

ꢄ

R_heat

P_heat

ꢅꢅ

1.5

10

2.5

16

ꢀ_ℎꢁꢂꢃ

=

ꢆ

ꢇꢈꢉꢊ

12.5

mW

Table 4 Electrical Specifications

Timing Specifications

V_dd= 5V 25°C

Characteristics

Symbol

Min

Typ

Max

1

Unit

ms

Notes / Conditions

Power Up Time

Soft Reset Time

15

Duration of Reset Pulse

3

Humidity OSR = 3

(0.007%RH)

7.8

ms

Humidity OSR = 2

(0.010%RH)

3.9

2.0

T_{conv hum}

Humidity Conversion Time

Humidity OSR = 1

(0.014%RH)

ms

Humidity OSR = 0

(0.020%RH)

1.0

12.1

6.1

3.1

1.6

Temperature OSR = 3

(0.012°C)

Temperature OSR = 2

(0.016°C)

T_{conv temp}

Temperature Conversion Time

Temperature OSR = 1

(0.025°C)

Temperature OSR = 0

(0.040°C)

Table 5 Timing Specifications

⁹One RH and temperature measurement per second, OSR0

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

INTERFACES

Pin Assignment

N° Function

Description

Serial Data Output / Input

Ground

1

2

3

4

5

6

SDA

GND

IC_Add

RST

Address Selection

Reset

VDD

SCL

Supply Voltage

Clock

Table 6 Pin Assignment

I²C Communication Pins (SDA / SCL)

SCL is used to synchronize the communication between microcontroller and HTU31D sensor. Since the interface consists of

fully static logic there is no minimum SCL frequency. The SDA pin is used to transfer data in and out of the device. To send a

command to HTU31D sensor, SDA is valid on the rising edge of SCL and shall remain stable while SCL is high. Following the

falling edge of SCL, SDA value may be changed. To guaranty safe communication SDA shall be valid tQS and tQH before the

rising and after the falling edge of SCL, respectively. To read data from HTU31D sensor, SDA is valid tVD after SCL has gone

low and remains valid until the next SCL falling edge.

An external pull-up resistor (e.g. 10kΩ¹⁰) on SCL and SDA is required to pull the signal high only for open collector or open drain

technology microcontrollers. In most case, pull-up resistors are internally included in I/O microcontroller circuits.

Figure 4 I2C Typical Application Circuit

Power Pins (VDD / GND)

Typical circuit includes a 100nF decoupling capacitor between VDD and GND, located as close as possible to the sensor.

IC_Add Pin

The IC_Add pin allows the user to dynamically change sensor I2C address to connect multiple sensors on the same I2C network.

The level applied to the IC_Add pin shall remain constant from the start to the end of the 2C communication (see Communication

and Operation section). If IC_Add pin is not used, it is recommended to connect it to GND (I2C address 0x40) or VDD with a

10kΩ series resistance (I2C address 0x41) as represented in Figure 4 I2C Typical Application Circuit.

RST Pin

The RST pin can be used to generate a reset of the sensor. A minimum pulse of 1 μs is required to reliably trigger a sensor

reset. If RST pin is not used, it is recommended to connect it to VDD with a 10kΩ series resistance.

¹⁰Pull-up resistor value is valid if the HTU is alone on I²C bus functioning at 100kHz, otherwise please refer to UM10204, Rev. 6, April 4, 2014

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

COMMUNICATION AND OPERATION

I²C Address

HTU31 series has the capability to respond 2 distinct I²C addresses. This feature allows to use multiple sensors on the same

I²C network and avoid address conflict with other components.

Hardwired Dynamic Address

The hardwired address is defined by the IC_ADD pin level (it sets the LSB value). It can be used to connect 2 sensors on the

same I²C network (one wired to VDD, the other to GND). To connect more than 2 sensors on the same I²C network, individual

IC_ADD lines can be used.

IC_ADD Pin level

Sensor I2C address (Hex)

GND

VDD

0x40

0x41

Table 7 Sensor I²C Address

Software Address

By default, the software address is not activated however it can be set to any I²C valid address by TE Connectivity upon request.

Input / Output Characteristics

Characteristic

Symbol

VOL

Min

Max

0.2 V_DD

V_DD

Unit

V

Output Low Voltage

Output High Voltage

Input Low Voltage

Input High Voltage

0.0 V_DD

VOH

VIL

0.8V_DD

V

0.0 V_DD

0.7 V_DD

0.3 V_DD

V_DD

V

VIH

V

Table 8 Input and Output Characteristics

Timing Specifications of Digital input/output pads for I²C Fast Mode

Characteristics

Symbol

fscl

Min

Typ

Max

Unit

MHz

ns

Notes / Conditions

SCL frequency

10

SCL high time

tlow

40

60

20

SCL low time

thigh

ns

SCL setup to falling SDA

SCL hold to falling SDA

SDA setup to SCL rising

SDA hold to SCL falling

tsu:sta

thd:sta

tsu:dat

thd:dat

ns

repeated start

signaling start

ns

SDA input

SDA output, internal chip

delay without loading

SDA delay to SCL falling

tsu:dout

5

20

ns

Table 9 Timing Specifications for I²C Fast Mode

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Sensor Functions

General

Every I²C message starts with the start condition and it is ended with the stop condition. Every command consists of two bytes:

the address byte and the command byte. The sensor address is 1000’00x. The x in the address is defined with the value at the

input of the I2C_LSB pin. If I2C_LSB =0 then the address will be 1000’000 (0x40), while if the I2C_LSB = 1 then the address

will be 1000’001 (0x41). This feature allows two sensors to operate on the same I2C bus.

7

6

5

4

3

2

1

0

Command Byte

Command Name

Conversion

Read T & RH

Read RH

CMD

Stop

X

0

1

0

OSRRH1

OSRRH0

OSRT1

OSRT0

0

1

0

1

0

1

0

1

0

1

0

1

0

X

Reset

X

Heater on

X

Heater off

X

Read serial number

Read Diagnostic

X

Table 10 User Commands

Temperature & Humidity Measurement Sequence

1) Execute “Conversion” command with the desired resolution to perform measurement and load it in sensor memory

2) Wait for the conversion time (see Table 5 Timing Specifications)

3) Execute “Read T & RH” or “Read RH” command to read measurement

Note: Humidity and temperature values will be updated by the “Conversion” command.

Conversion

The conversion command triggers a single temperature and humidity conversion with Selected Resolution OSR:

Figure 5 Conversion Command

Abbreviation

Binary value

Description

osrRH1..osrRH0

11

10

01

00

11

10

01

00

Humidity OSR = 3 (0.007%RH)

Humidity OSR = 2 (0.010%RH)

Humidity OSR = 1 (0.014%RH)

Humidity OSR = 0 (0.020%RH)

Temperature OSR = 3 (0.012°C)

Temperature OSR = 2 (0.016°C)

Temperature OSR = 1 (0.025°C)

Temperature OSR = 0 (0.040°C)

osrT1..osrT0

Table 11 Humidity and Temperature Conversion Parameters and Associated Resolution

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Read T & RH

The Read T & RH command can be used either to read only the temperature or both the temperature and the humidity. The 16

temperature data bits are followed by an 8-bit temperature CRC. The 16 RH data bits are followed by an 8-bit RH CRC. The

data reading can be stopped any time by sending a not acknowledge (nack) and stop sequence. This can be used, for example,

when only the temperature data is needed.

Figure 6 Read T&RH command

Note: The not acknowledge (nack) and stop at the end of the reading is mandatory, otherwise the chip may block the SDA.

Read RH

The Read RH command is available when only the relative humidity (RH) data is needed. The 16 RH data bits are followed by

an 8-bit CRC. When the CRC is not required, the data reading can be stopped after the 16 RH data bits by sending a not

acknowledge (nack) and stop sequence.

Figure 7 Read RH Command

Note: The not acknowledge (nack) and stop at the end of the reading is mandatory, otherwise the chip may block the SDA.

TE CONNECTIVITY SENSORS /// HTU31D RH/T SENSOR IC

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Reset

Reset command is used to reboot the HTU31D switching the power off and on again. Upon reception of this command, the

HTU31D reinitializes and starts operation according to the default settings. The reset takes less than 5ms.

Figure 8 Soft Reset Command

Heater on

The sensor includes a built-in heater which can be switched on by the following command:

Figure 9 Heater on Command

Heater off

To switch the heater off, a reset command or the following command must be applied:

Figure 10 Heater off Command

Read serial number

For identification of the chip, the serial number can be read. The 24-bit serial number data is followed by an 8-bit CRC:

Figure 11 Read serial number Command

Note: The not acknowledge (nack) and stop at the end of the reading is mandatory, otherwise the chip may block the SDA.

TE CONNECTIVITY SENSORS /// HTU31D RH/T SENSOR IC

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Read Diagnostic

A diagnostic register is available to check if the humidity and temperature are working properly, if the humidity or temperature

are out of specified range, the heater and the memory status:

Figure 12 Read Serial number command

Note: The not acknowledge (nack) and stop at the end of the reading is mandatory, otherwise the chip may block the SDA.

Diagnostic Register

7

6

5

4

3

2

1

0

NVM error

(NVM err)

Humidity

under/overrun high error

(Hout) (Hhigh)

Humidity

low error

(Hlow)

Temperature

under/overrun high error

(Tout) (Thigh)

Temperature Temperature

Heater on

(Hon)

low error

(Tlow)

Table 12 Diagnostic Register

Abbreviation

Description

NVM error (NVM err)

bit is set if the CRC of the NVM has failed (CRC is done on the register copy)

bit is set if the humidity is truncated to 0 or the max value of 2^16-1

bit is set if the humidity calculation results above 120 %RH

bit is set if the humidity calculation results below -10 %RH

bit is set if the temperature is truncated to 0 or the max value of 2^16-1

bit is set if the temperature calculation results above 150 °C

bit is set if the temperature calculation results below -50 °C

bit is set if the heater is on

Humidity under/overrun (Hout)

Humidity high error (Hhigh)

Humidity low error (Hlow)

Temperature under/overrun (Tout)

Temperature high error (Thigh)

Temperature low error (Tlow)

Heater on (Hon)

Table 13 Diagnostic Register Bits Description

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

CRC

CRC Checksum

HTU31D sensor includes a CRC-8 checksum for error detection. The polynomial used is X⁸+ X⁵+ X⁴+ 1.

Basic Considerations

CRC stands for Cyclic Redundancy Check. It is one of the most effective error detection schemes and requires a minimal amount

of resources.

The types of detectable errors with CRC implemented in HTU31D sensors are:

•

Any odd number of errors anywhere in the data transmission

All double-bit errors anywhere in the data transmission

Any cluster of errors that can be contained within an 8-bit window (1-8 bits incorrect)

Most larger clusters of errors

A CRC is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw

data.

Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their

contents; on retrieval the calculation is repeated, and corrective action can be taken against presumed data corruption if the

check values do not match.

CRCs are so called because the check (data verification) value is a redundancy (it expands the message without adding

information) and the algorithm is based on cyclic codes. CRCs are popular because they are simple to implement in binary

hardware, easy to analyze mathematically, and particularly effective to detect common errors caused by noise in transmission

channels. As the check value has a fixed length, the function that generates it is occasionally used as a hash function.

When HTU31D operates with standard I²C protocol, an 8-bit CRC can be used to detect transmission errors. The CRC covers

all read data transmitted by the sensor. CRC properties for HTU31D communicating with I²C protocol are listed below:

CRC with I²C protocol

X⁸+ X⁵+ X⁴+ 1

0x00

Generator polynomial

Initialization

Protected data

Final Operation

Read data

none

Table 14 I²C CRC Properties

CRC Calculation

To compute a n-bit binary CRC, line bits representing the input in a row, and position the (n+1)-bit pattern representing the

CRC's divisor (called a "polynomial") underneath the left-hand end of the row. This is first padded with zeroes corresponding to

the bit length n of the CRC. If the input bit above the leftmost divisor bit is 0, do nothing. If the input bit above the left most divisor

bit is 1, the divisor is XORed into the input (in other words, the input bit above each 1-bit in the divisor is toggled). The divisor is

then shifted one bit to the right, and the process is repeated until the divisor reaches the right-hand end of the input row. Since

the left most divisor bit zeroed every input bit it touched, when this process ends the only bits in the input row that can be non-

zero are the n bits at the right-hand end of the row. These n bits are the remainder of the division step and will also be the value

of the CRC function. The validity of a received message can easily be verified by performing the above calculation again, this

time with the check value added instead of zeroes. The remainder should equal zero if there are no detectable errors.

CRC Examples

The input message 11011100 (0xDC) will have as result 01111001 (0x79).

The input message 01101000 00111010 (0x683A) will have as result 01111100 (0x7C).

The input message 01001110 10000101 (0x4E85) will have as result 01101011 (0x6B).

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Conversion of Signal Outputs

Measurement data are transferred as 16-bit values (unsigned integer).

Converting those raw values into a physical measurement can be achieved using the following formulas:

Relative Humidity Conversion

From the relative humidity output S_RH(decimal), the relative humidity RH (%RH) is obtained by the following formula, this formula

being applicable whatever selected resolution (OSR):

S_RH

RH =100×

2¹⁶−1

Temperature Conversion

From the temperature output S_T(decimal), the temperature T (°C) is obtained by the following formula, this formula being

applicable whatever selected resolution (OSR):

S_T

T = −40 +165×

2¹⁶−1

Note: these formulas are only valid with decimal representation of S_Tand S_RH

Dew Point Temperature Calculation

The dew point is the temperature at which the water vapor in the air becomes saturated and condensation begins.

The dew point is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current

air temperature. Relative humidity of 100% indicates that the dew point is equal to the current temperature (and the air is

maximally saturated with water). When the dew point stays constant and temperature increases, relative humidity will decrease.

Partial Pressure (PPTamb) Calculation from Ambient Temperature

Partial Pressure (PPTamb) is calculated using temperature measurement from HTU31 sensor with the following formula:

PP_TambPartial Pressure in mmHg at Ambient Temperature





B

A−





PP =10^^

T_amb

Ambient Temperature in °C, from HTU31

(Tamb+C)

Tamb

A, B, C Constants: A=8.1332; B=1762.39; C=235.66

Dew Point Temperature (T ) Calculation from Partial Pressure (PPTamb)

d

Dew point temperature (Td) of the air is calculated using ambient relative humidity and temperature measurements from HTU31

sensor with the following formula:

PP_TambPartial Pressure in mmHg at Ambient Temperature









RH_ambAmbient Relative Humidity in %RH, from HTU31

B

T_amb

T_d

Ambient Temperature in °C, from HTU31

Calculated Dew Point in °C

T_d= −

+ C

PP







Tamb

log RH

×

− A



amb

¹⁰











100

A, B, C Constants: A=8.1332; B=1762.39; C=235.66

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

PACKAGING AND ASSEMBLY INFORMATION

Package Outline

Bottom View

Side View

Top View

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Packaging Type

HTU31 is provided in DFN type package (Dual Flat No leads).

The HTU31 sensor chip is mounted on a lead frame made of Cu and plated with Ni/Pd/Au.

Traceability Information

Every HTU31D is laser marked with an alphanumeric code. The marking consists of two lines of digits:

•

The first line denotes the sensor type: HTU31.

The second line denotes HTU31 output mode and Date Code as:

o

The first digit of the second line defines the HTU31 output mode:

.

D = Digital (I²C)

V = Analog

o

The second and third digits define the manufacturing year: 19=2019, 20=2020.

The last three digits represent the day of the year.

Reels are also labeled for lot identification and additional traceability information, as displayed below:

With:

3X:

Sensor Type (31 for HTU31)

Output mode (V = Analog)

MEAS Traceability Code

Y:

TTTTTTTTT:

QQQQ:

YY:

Quantity per reel (400, 1500 or 5000 units)

Last two digits of the year

Day of the year

DDD:

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HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

Tape & Reel Packaging

HTU31D sensors are delivered in tape & reel packaging, sealed into antistatic ESD bags.

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.

For 400 and 1500 units: outside diameter of 7” (178mm) and a 1/2” (13mm) diameter arbor hole.

For 5000 units: outside diameter of 13” (330mm) and a 1/2” (13mm) diameter arbor hole.

Figure 13 Tape and Reel Drawing

Figure 14 Product Orientation in Tape and Reel Packaging

Recommended Footprint for PCBa Assembly

Figure 15 Recommended footprint (All dimensions are in mm)

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Digital Relative Humidity & Temperature Sensor

Handling & Storage Recommendations

To guaranty and preserve the high-quality performance of the HTU31 sensor, the following recommendations shall be respected

concerning storage and packaging:

Prior sensors use or assembly, it is recommended to store them in their original sealed anti ESD packaging. If sensors have

been removed from their original packaging, it is recommended to keep them in anti-static shielded ESD bags.

HTU31 sensor shall not be in contact with volatile chemicals such as solvents or other organic compounds that could induce a

sensing element pollution or damage.

HTU31 sensor is classified MSL level 1 according to IPC/JEDEC J-STD-020.1 for storage, packaging and handling.

The typical shelf life is 1 year at temperature below 30°C and relative humidity below 85%RH.

HTU31 sensor shall be protected from ESD (Electrostatic Discharge) and shall be handled in ESD protected areas (EPA) under

protected and standard controlled conditions (ground with wrist-straps, ground all non-insulating and conductive objects, operate

only in grounded conductive floor.

Figure 16 Protection against ESD mandatory

Soldering and Assembly Instructions

HTU31 sensor is designed 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 reflow ovens.

Figure 17 Reflow Soldering profile according to JEDEC standard

Standard pick & place equipment and vacuum nozzles for standard DFN packages may be used for assembly of HTU31 sensors.

For manual soldering contact time must be limited to 5 seconds at 350°C.

The use of “no clean” solder paste is recommended to avoid pollution or damage of RH sensing element.

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.

No board wash shall be applied to HTU31 sensors without appropriate sensor upper surface adhesive tape protection.

No coating shall be applied to HTU31 sensors without appropriate sensor upper surface adhesive tape protection.

Immediately after soldering high thermal stress, HTU31 sensors may temporarily read a normal slight RH negative deviation (<

1%RH) corresponding to sensing element extreme drying. This slight normal deviation will disappear after one or two days.

TE CONNECTIVITY SENSORS /// HTU31D RH/T SENSOR IC

REV3 01/2021

Page 17

HTU31D RH/T SENSOR IC

Digital Relative Humidity & Temperature Sensor

ORDERING INFORMATION

Output Signal

Part Number

D

V

I²C Digital

HTU31x

Ratiometric Voltage

Description

Quantity

Part number

HTU31D RH/T IC DIGITAL R400 (New ESD 4kV)

HTU31D RH/T IC DIGITAL R1500 (New ESD 4kV)

HTU31D RH/T IC DIGITAL R5000 (New ESD 4kV)

HTU31D RH/T IC DIGITAL R400 (ESD 2kV)

HTU31D RH/T IC DIGITAL R1500 (ESD 2kV)

HTU31D RH/T IC DIGITAL R5000 (ESD 2kV)

HTU31V RH/T IC ANALOG R400 (New ESD 4kV)

HTU31V RH/T IC ANALOG R1500 (New ESD 4kV)

HTU31V RH/T IC ANALOG R5000 (New ESD 4kV)

HTU31V RH/T IC ANALOG R400 (ESD 2kV)

HTU31V RH/T IC ANALOG R1500 (ESD 2kV)

HTU31V RH/T IC ANALOG R5000 (ESD 2kV)

Demonstration Board HTU31D

400

1500

5000

400

10142048-20

10142048-21

10142048-22

10142048-00

10142048-01

10142048-02

10142048-30

10142048-31

10142048-32

10142048-10

10142048-11

10142048-12

10142605-10

10142605-02

1500

5000

400

1500

5000

400

1500

5000

1

Demonstration Board HTU31V

1

REVISION HISTORY

DATE

VERSION

PAGE(S)

2 / 4 / 6 / 18

CHANGES

January 2021

3

Update of Humidity Response Time, Long-Term Drift, and ESD. /

Interfaces / Part number updates

›

CLICK HERE

CONNECT WITH A SPECIALIST

NORTH AMERICA

Tel +1 800 522 6752

EUROPE

Tel +31 73 624 6999

ASIA

Tel +86 0400 820 6015

te.com/sensors

TE Connectivity, TE, TE Connectivity (logo) and Every Connection Counts are trademarks. All other logos, products and/or company names referred to herein might

be trademarks of their respective owners

The information given herein, including drawings, illustrations and schematics which are intended for illustration purposes only, is believed to be reliable. However,

TE Connectivity makes no warranties as to its accuracy or completeness and disclaims any liability in connection with its use. TE Connectivity‘s obligations shall

only be as set forth in TE Connectivity‘s Standard Terms and Conditions of Sale for this product and in no case will TE Connectivity be liable for any incidental,

indirect or consequential damages arising out of the sale, resale, use or misuse of the product. Users of TE Connectivity products should make their own evaluation

to determine the suitability of each such product for the specific application.

Version #3 01/2021

TE CONNECTIVITY SENSORS /// HTU31D RH/T SENSOR IC

REV3 01/2021

Page 18

te.com

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

Characteristics

• Fully calibrated, temperature compensated

• High accuracy: ±2%RH and ±0.2°C

• Fast humidity response time: 5s

• Wide supply voltage range from 3V to 5.5V

• Low average current: 161µA typical

• Compact 6-Pin DFN package: 2.5x2.5x0.9mm

• Ratiometric voltage output

• Fully RoHS and REACH compliant

Features

• High Reliability and Robustness

• Fast Recovery after Saturation

• Fully Compatible with Reflow Process

General Description

• Fully Interchangeable without

The HTU31 is one of the smallest and most accurate humidity sensors on

the market. TE Connectivity precision engineering and 20+ years of

experience in humidity and temperature combination sensors, enabled this

new product with fast response time, precision measurement, low

hysteresis, robustness to reflow assembly process and sustained

performance even when exposed to extreme temperature [-40° to 125°C]

and humidity [0%RH to 100%RH] environments.

Calibration

• Serial Individual Marking for Traceability

• Lead Free

• Low Power Consumption

Applications

HTU31 humidity & temperature sensor includes both digital (D) and analog

(V) versions and combines multiple functions with an application-friendly

operating supply voltage range from 3V to 5.5V.

• Home Appliance

• Medical

• Printers

HTU31 sensor is available in small and large volumes to meet the ever-

changing demands of our customers.

• Humidifiers

• Automotive

• Meteorology

• Environmental Monitoring & Trackers

›

CLICK HERE

CONNECT WITH A SPECIALIST

Page 1

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

PERFORMANCE SPECIFICATIONS

Relative Humidity Specifications

V

_dd= 5V 25°C

Characteristics

Condition

Max¹

Value

0 to 100

±2

Units

%RH

Notes / Conditions

Humidity Operating Range

Relative Humidity Accuracy

Typical

Figure 1 Humidity

Sensor Rating @25°C

Resolution

Typical

0.01

%RH

Table 11 Humidity and

Temperature

Conversion Parameters

Hysteresis

@25°C

τ_63%

±0.7

5

%RH

Response Time²

s

Recovery Time after Condensation³

Long Term Drift⁴

Typical

10

s

<0.25

%RH / year

Table 1 Humidity Specifications

Temperature Specifications

V_dd= 5V 25°C

Characteristics

Condition

Value

-40 to 125

±0.2

Units

°C

Notes / Conditions

Temperature Operating Range

Temperature Accuracy

Typical

°C

Figure 2 Temperature

Sensor Rating

Resolution

0.016

°C

Table 11 Humidity and

Temperature

Conversion Parameters

Response Time²

Long Term Drift

10

s

τ_63%

Typical

0.04

°C / year

Table 2 Temperature Specifications

¹Cf. Figure 3 Humidity and Temperature Operating Range

²With 1m.s^-1air flow

³Measured according to AFNOR standard NFX 15-113, with 3 m.s^-1air flow

⁴Typical application in regular environmental variation within optimum measurement range

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 2

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

Humidity Sensor Rating

10

9

8

7

6

5

4

3

2

1

0

Maximal Tolerance

Typical Tolerance

0

10

20

30

40

50

60

70

80

90

100

Relative Humidity (%RH)

Figure 1 Humidity Sensor Rating @25°C

Temperature Sensor Rating

2

1.8

1.6

1.4

1.2

1

Maximal Tolerance

Typical Tolerance

0.8

0.6

0.4

0.2

0

-40

-20

0

20

40

60

80

100

120

Temperature (°C)

Figure 2 Temperature Sensor Rating

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 3

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

SENSOR INTEGRATION

Absolute Maximum Operating Conditions

Ratings

Symbol

Tstg

Vcc

Value

-40 to 150

Unit

Notes / Conditions

Storage Temperature⁵

Supply Voltage (Peak)

Humidity Operating Range

Temperature Operating Range

VDD to GND

°C

Vdc

%RH

°C

5.5

0 to 100

-40 to +125

-0.3 to 5.5

±4

RH

Ta

V

ESD HBM (Human Body Model)⁶

ESD CDM (Charged Device Model)⁷

Latch Up Sensitivity⁸

kV

750

V

±300

mA

Table 3 Maximum Operating Conditions

Figure 3 Humidity and Temperature Operating Range

The sensor should operate at peak condition less than 10% of the operating life. Exposure to absolute maximum

humidity/temperature conditions for extended periods may temporarily induce an offset on RH measurement (+5%RH above

accuracy specifications, which will recover over time) and accelerate its ageing.

⁵Sensor in specifications after 1000h storage @150°C

⁶According to ANSI/ESDA/JEDEC JS-001-2017, AEC-Q100-002.

⁷According to JESD22-C101, AEC-Q100-011

⁸According to JESD78

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 4

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

Electrical Specifications

V_dd= 5V 25°C

Characteristics

Supply Voltage

Symbol

Min

Typ

5.0

Max

Unit

V

Notes / Conditions

V_dd

i_dd

3.0

5.5

161

511

805

2.55

µA

µW

mW

µA

nF

Typical

Peak

Current Consumption

Power Dissipation

Typical

Peak

Buffer Output Current

Buffer Capacitive Load

±200

5.0

0.0

Table 4 Electrical Specifications

Timing Specifications

V_dd= 5V 25°C

Characteristics

Symbol

Min

Typ

Max

Unit

Notes / Conditions

Power Up Time

10

ms

Table 5 Timing Specifications

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 5

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

INTERFACES

Pin Assignment

N° Function

Description

1

2

3

4

5

6

RH

RH Ratiometric Voltage Output

Ground

GND

BUF

RST

VDD

TEMP

Buffer Off Control

Reset

Supply Voltage

Temp. Ratiometric Voltage Output

Table 6 Pin Assignment

Relative Humidity and Temperature Ratiometric Voltage Output Pins (RH / TEMP)

Relative humidity voltage output is directly provided via RH pin. Temperature voltage output is directly provided via TEMP pin.

Figure 4 HTU31V Typical Application Circuit

Power Pins (VDD / GND)

Typical circuit includes a 100nF decoupling capacitor between VDD and GND, located as close as possible to the sensor.

BUF Pin

The HTU31V includes a built-in output buffer for the two voltage RH and temperature outputs.

The BUF pin is used to enable or disable this output buffer.

-

When BUF pin is connected to GND, as represented in Figure 4 HTU31V Typical Application Circuit, voltage output

buffer is on, this is the recommended configuration for most applications.

-

When BUF pin is connected to VDD, analog output buffer is off, the voltage outputs will be at high impedance, an

external buffer is then highly recommended. Loading on RH and TEMP pins must be higher than 1GΩ to avoid nonlinear

effects.

RST Pin

The RST pin can be used to generate a reset of the sensor. A minimum pulse of 1μs is required to reliably trigger a sensor reset.

-

When RST pin is connected to GND, chip in reset / power down mode.

When RST pin is connected to VDD, chip is in operating mode.

If reset feature is not used, RST pin must be connected to VDD, as represented in Figure 4 HTU31V Typical Application Circuit.

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 6

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

COMMUNICATION AND OPERATION

Conversion of Ratiometric Voltage Outputs

Relative Humidity Conversion

From the voltage output ꢀ_ꢁꢂ, updated each 250ms, the relative humidity in %RH is obtained by the following formula:

ꢀ_ꢁꢂ

ꢀ_ꢅꢅ

10 100 ꢀ_ꢁꢂ

(

)

ꢃꢄ % = −12,5 + 125 .

= −

+

.

0,8 0,8 ꢀ_ꢅꢅ

Figure 5 Relationship between ratiometric voltage output and measured relative humidity in %RH

Temperature Conversion

From the voltage output ꢀ_ꢆ, updated each 250ms, the temperature T in °C or in °F is obtained by the following formulas:

ꢀ_ꢆ

16,5 165 ꢀ_ꢆ

(

)

ꢇ °ꢈ = −60,625 + 206,25 .

= −40 −

+

.

ꢀ_ꢅꢅ

0,8

0,8 ꢀ_ꢅꢅ

ꢀ_ꢆ

29,7 297 ꢀ_ꢆ

(

)

ꢇ °ꢉ = −77,125 + 371,25 .

+

.

ꢀ_ꢅꢅ

0,8

0,8 ꢀ_ꢅꢅ

Figure 6 Relationship between ratiometric voltage output and measured temperature in °C and °F

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 7

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

Error Codes

Relative Humidity

In case of abnormal open circuit, the voltage output ꢀ_ꢁꢂwill provide an error code : ꢀ_ꢁꢂ=0V.

In case of abnormal short circuit, the voltage output ꢀ_ꢁꢂwill provide an error code : ꢀ_ꢁꢂ=ꢀ_ꢅꢅ

.

Temperature

In case of abnormal open circuit or values below -50°C, the voltage output ꢀ_ꢆwill provide an error code : ꢀ_ꢆ=0V.

ꢊ

ꢋ

In case of values between -50°C and -40°C, the voltage output ꢀ_ꢆwill provide a clamping : ꢀ_ꢆ=

= 10%.

ꢊ_ꢌꢌ

ꢊ

ꢋ

In case of values between 125°C and 150°C, the voltage output ꢀ_ꢆwill provide a clamping : ꢀ_ꢆ=

= 90%.

ꢊ_ꢌꢌ

In case of abnormal short circuit or values above 150°C, the voltage output ꢀ_ꢆwill provide an error code : ꢀ_ꢆ=ꢀ_ꢅꢅ

.

Dew Point Temperature Calculation

The dew point is the temperature at which the water vapor in the air becomes saturated and condensation begins.

The dew point is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current

air temperature. Relative humidity of 100% indicates that the dew point is equal to the current temperature (and the air is

maximally saturated with water). When the dew point stays constant and temperature increases, relative humidity will decrease.

Partial Pressure (PPTamb) Calculation from Ambient Temperature

Partial Pressure (PPTamb) is calculated using temperature measurement from HTU31 sensor with the following formula:

PP_TambPartial Pressure in mmHg at Ambient Temperature





B

A−





PP =10^^

T_amb

Ambient Temperature in °C, from HTU31

(Tamb+C)

Tamb

A, B, C Constants: A=8.1332; B=1762.39; C=235.66

Dew Point Temperature (T ) Calculation from Partial Pressure (PPTamb)

d

Dew point temperature (Td) of the air is calculated using ambient relative humidity and temperature measurements from HTU31

sensor with the following formula:

PP_TambPartial Pressure in mmHg at Ambient Temperature









RH_ambAmbient Relative Humidity in %RH, from HTU31

B

T_amb

T_d

Ambient Temperature in °C, from HTU31

Calculated Dew Point in °C

T_d= −

+ C

PP







Tamb

log RH

×

− A



¹⁰



amb









100

A, B, C Constants: A=8.1332; B=1762.39; C=235.66

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 8

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

PACKAGING AND ASSEMBLY INFORMATION

Package Outline

Bottom View

Side View

Top View

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 9

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

Packaging Type

HTU31 is provided in DFN type package (Dual Flat No leads).

The HTU31 sensor chip is mounted on a lead frame made of Cu and plated with Ni/Pd/Au.

Traceability Information

Every HTU31V is laser marked with an alphanumeric code. The marking consists of two lines of digits:

•

The first line denotes the sensor type: HTU31.

The second line denotes HTU31 output mode and Date Code as:

o

The first digit of the second line defines the HTU31 output mode:

.

D = Digital (I²C)

V = Analog

o

The second and third digits define the manufacturing year: 19=2019, 20=2020.

The last three digits represent the day of the year.

Reels are also labeled for lot identification and additional traceability information, as displayed below:

With:

3X:

Sensor Type (31 for HTU31)

Output mode (V = Analog)

MEAS Traceability Code

Y:

TTTTTTTTT:

QQQQ:

YY:

Quantity per reel (400, 1500 or 5000 units)

Last two digits of the year

Day of the year

DDD:

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 10

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

Tape & Reel Packaging

HTU31V sensors are delivered in tape & reel packaging, sealed into antistatic ESD bags.

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.

For 400 and 1500 units: outside diameter of 7” (178mm) and a 1/2” (13mm) diameter arbor hole.

For 5000 units: outside diameter of 13” (330mm) and a 1/2” (13mm) diameter arbor hole.

Figure 7 Tape and Reel Drawing

Figure 8 Product Orientation in Tape and Reel Packaging

Recommended Footprint for PCBa Assembly

Figure 9 Recommended footprint (All dimensions are in mm)

TE CONNECTIVITY SENSORS /// HTU31V RH/T SENSOR IC

REV3 01/2021

Page 11

HTU31V RH/T SENSOR IC

Analog Relative Humidity & Temperature Sensor

Handling & Storage Recommendations

To guaranty and preserve the high-quality performance of the HTU31 sensor, the following recommendations shall be respected

concerning storage and packaging:

Prior sensors use or assembly, it is recommended to store them in their original sealed anti ESD packaging. If sensors have

been removed from their original packaging, it is recommended to keep them in anti-static shielded ESD bags.

HTU31 sensor shall not be in contact with volatile chemicals such as solvents or other organic compounds that could induce a

sensing element pollution or damage.

HTU31 sensor is classified MSL level 1 according to IPC/JEDEC J-STD-020.1 for storage, packaging and handling.

The typical shelf life is 1 year at temperature below 30°C and relative humidity below 85%RH.

HTU31 sensor shall be protected from ESD (Electrostatic Discharge) and shall be handled in ESD protected areas (EPA) under

protected and standard controlled conditions (ground with wrist-straps, ground all non-insulating and conductive objects, operate

only in grounded conductive floor.

Figure 10 Protection against ESD mandatory

Soldering and Assembly Instructions

HTU31 sensor is designed 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 reflow ovens.

Figure 11 Reflow Soldering profile according to JEDEC standard