HUMIDITY SENSOR WITH INTEGRATED
TEMPERATURE SENSOR
WSEN-HIDS
USER MANUAL
2525020210001
VERSION 1.3
DECEMBER 8, 2020
Revision history
Manual
version
1.0 1.0
1.1 1.0
1.2 1.0
1.3 1.0
Product
version
Notes
• Initial release of the manual
• Temperature measurement range is
changed in chapter 2.2
• Slave address of the humidity sensor
changed
• I2C multiple byte read operation
chapter added
• Chapter 7.2: Flow chart updated
• Chapter 9: Sensor output data
updated
Date
September 2020
October 2020
October 2020
December 2020
Humidity sensor with integrated temperature sensor, Part Nr. 2525020210001
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Abbreviations
Abbreviation Description
BDU Block update data
DRDY Data ready
ESD Electrostatic discharge
FIFO First-in first-out
I2C Inter integrated circuit
LGA Land grid array
LSB Least significant bit
MEMS Micro-Electro Mechanical system
MSB Most significant bit
ODR Output data rate
PCB Printed circuit board
SPI Serial peripheral interface
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Contents
1 Product description 6
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3 Sensor features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Sensor and electrical specifications 8
2.1 Humidity sensor specifications . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Temperature sensor specifications . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4 Absolute maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.5 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3 Pinning description 11
4 Application circuit 12
5 Digital interface 13
5.1 General characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2 SDA and SCL logic levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3 Communication phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3.1 Idle state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3.2 START(S) and STOP(P) condition . . . . . . . . . . . . . . . . . . . 14
5.3.3 Data validity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3.4 Byte format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.3.5 Acknowledge (ACK) and No-Acknowledge (NAACK) . . . . . . . . 15
5.3.6 Slave address for the sensor . . . . . . . . . . . . . . . . . . . . . . 15
5.3.7 Read/Write operation . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.4 I2C Multiple bytes read operation . . . . . . . . . . . . . . . . . . . . . . . . 17
5.5 I2C timing parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6 Serial Peripheral Interface (SPI) 19
6.1 Data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.2 Communication modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.3 Sensor SPI Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.3.1 SPI write operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.3.2 SPI read operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.3.3 SPI timing parameters . . . . . . . . . . . . . . . . . . . . . . . . . 23
7 Quick start guide 24
7.1 Communication check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.2 Sensor in operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8 Operating modes 26
8.1 Continuous mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.2 One shot mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
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9 Sensor output data 28
9.1 Humidity sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.2 Steps to calculate humidity output value . . . . . . . . . . . . . . . . . . . . 28
9.3 Temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
9.4 Steps to compute temperature output value . . . . . . . . . . . . . . . . . . 29
10 Sensor register mapping 31
10.1 Calibration Register mapping . . . . . . . . . . . . . . . . . . . . . . . . . . 32
11 Register description 33
11.1 Device_ID (0x0F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
11.2 Average (0x10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
11.3 CTRL_1 (0x20) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
11.3.1 Block data update (BDU) . . . . . . . . . . . . . . . . . . . . . . . . 34
11.4 CTRL_2 (0x21) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
11.4.1 BOOT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
11.4.2 Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
11.5 CTRL_3 (0x22) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.6 STATUS (0x27) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.7 H_OUT_L (0x28) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
11.8 H_OUT_H (0x29) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
11.9 T_OUT_L (0x2A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
11.10 T_OUT_H (0x2B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
12 Handling humidity sensor 39
13 Physical dimensions 40
13.1 Module drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
13.2 Footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
14 Manufacturing information 42
14.1 Moisture sensitivity level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
14.2 Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
14.2.1 Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
14.2.2 Cleaning and washing . . . . . . . . . . . . . . . . . . . . . . . . . 44
14.2.3 Potting and coating . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
14.2.4 Storage conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
14.2.5 Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
15 Important notes 46
15.1 General customer responsibility . . . . . . . . . . . . . . . . . . . . . . . . . 46
15.2 Customer responsibility related to specific, in particular safety-relevant ap-
plications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
15.3 Best care and attention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
15.4 Customer support for product specifications . . . . . . . . . . . . . . . . . . 46
15.5 Product improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
15.6 Product life cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
15.7 Property rights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
15.8 General terms and conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Humidity sensor with integrated temperature sensor, Part Nr. 2525020210001
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16 Legal notice 48
16.1 Exclusion of liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
16.2 Suitability in customer applications . . . . . . . . . . . . . . . . . . . . . . . 48
16.3 Usage restriction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
17 License terms for Würth Elektronik eiSos GmbH & Co. KG sensor product
software and source code 50
17.1 Limited license . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
17.2 Usage and obligations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
17.3 Ownership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
17.4 Disclaimer of warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
17.5 Limitation of liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
17.6 Applicable law and jurisdiction . . . . . . . . . . . . . . . . . . . . . . . . . . 51
17.7 Severability clause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
17.8 Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
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1 Product description
0.9 mm
1.1 Introduction
The humidity sensor is a 16-bit digital ultra-low-power and high-performance sensor with
digital output interface. It measures relative humidity from 0 to 100% rH with an output data
rate of 1 Hz, 7 Hz and 12.5 Hz. It is embedded with a temperature sensor for ambient temperature measurement. The sensor is fully calibrated and no further calibration is required.
The dimension of the sensor is 2.0 mm×2.0 mm×0.9 mm. It is available in land grid array
package (LGA).
1.2 Applications
• HVAC systems
• Home and building automation
• Goods and asset tracking
• Air conditioners
• Refrigerators
1.3 Sensor features
• Humidity measurement range :
• Humidity noise :
• Temperature measurement range :
• Temperature noise :
• Output data rate :
• Operating modes :
• Current consumption :
• Communication interface :
0 to 100 % rH
0.35 rH % RMS
-40 to +120 °C
0.03 °C RMS
1 Hz, 7 Hz and 12.5 Hz
Continuous mode and one-shot mode
8.9µA @ODR 1Hz
I2C, SPI and Interrupt pin
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1.4 Block diagram
Multiplexer
ADC
Controller
Logic &
Interrupt
Op
Amp
Timming
Circuits
Voltage &
Current Bias
Digital
Interface
SDA
SCL
Clock
Generator
CS
INT
Humidity capacitor
sensing element
Temperature
Sensor
Figure 1: Block diagram
The sensor is a MEMS based capacitive humidity sensor with an integrated ASIC. MEMS
sensing element is a planar fringed capacitor with a dielectric polymer which absorbs or releases water with proportional to the relative humidity in the environment. A silicon based
temperature sensor is integrated in the same package. ASIC comprises of multiplier, operational amplifier, analog-to-digital converter and other signal conditioning blocks like controller
logics and interrupts. ASIC converts the analog signal from the both humidity and temperature sensing element into a 16-bit digital humidity and temperature values. The sensor is
factory calibrated for both humidity and temperature measurements. The trimming parameters are stored in on-chip flash memory. When the sensor is powered on, these trimming
parameters are loaded from the flash memory to the registers. Hence, no further calibration
is required for humidity and temperature values.
1.5 Ordering information
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WE order code Temperature Range Description
2525020210001 -40° C to +120° C Tape & reel packaging
Table 1: Ordering information
2 Sensor and electrical specifications
T=25°C, supply voltage VDD = 3.3V, unless otherwise stated.
2.1 Humidity sensor specifications
Parameters Symbol Test conditions Min.1Typ. Max.
1
Unit
Measurement range H
Resolution RES
Sensitivity SEN
Accuracy H
RANGE
H
H
ACC
20% rH to 80% rH ±3.5
0 100
16
0.004
0% rH to 100% rH ±5
Noise(RMS) H
Hystersis HYS
Long-term drift H
Response time H
NOISE
H
DRIFT
STEP
Internal average:
32 samples
2
0.35
±1
20% rH to 80% rH 0.5
Step response
time of 63%
10
Output data rate ODR 1 12.5
Table 2: Humidity sensor specification
1
Minimum and maximum values are based on characterization at 3σ.
2
Default setting
% rH
bits
% rH/digit
% rH
% rH
% rH RMS
% rH
% rH/Year
s
Hz
2.2 Temperature sensor specifications
Parameters
Measurement range
Resolution
Noise(RMS)
Sensitivity
Absolute accuracy
Symbol
T
RANGE
RES
T
NOISE
SEN
T
ACC_ABS
Test conditions
T
Internal average:
16 samples
T
2
15°C to 40°C ±0.5
0°C to 60°C ±1
Table 3: Temperature sensor specification
1
Minimum and maximum values are based on characterization at 3σ.
2
Default setting
1
Min.
-40 +120 °C
Typ.
16
0.03
0.016
Max.
1
°C RMS
Unit
bits
°C/digit
°C
°C
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2.3 Electrical specifications
Parameters
Operating supply voltage
Current consumption
Current consumption in
power down mode
Symbol
V
DD
I
DD
I
DD_PD
Test
conditions
ODR 1 Hz 8.9
Min.
1.7
1
Table 4: Electrical specification
1
Minimum and maximum values are based on characterization at 3σ.
2.4 Absolute maximum rating
Parameter
Input voltage VDDpin
Input voltage SDA, SCL &
CS
Symbol
V
DD
Test conditions
VINpins -0.3 V
Min.
-0.3 4.8 V
Typ.
3.3
0.5
1
Max.1Unit
3.6 V
Max.
DD_IO
1
+ 0.3 V
µA
µA
Unit
Table 5: Absolute maximum rating
1
Minimum and maximum values are based on characterization at 3σ.
Supply voltage on any pin should never exceed 4.8 V
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2.5 General information
Parameters Values
Operating temperature -40°C to +120°C
Storage temperature -40°C to +125°C
Communication interface I2C & SPI
Moisture sensitivity level (MSL) 3
Electrostatic discharge protection(HBM) 2 kV
The device is susceptible to damage by electrostatic discharge (ESD). Always
use proper ESD precautions when handling. Improper handling of the device
can cause performance degradation or permanent damage to the part
Table 6: General information
For better performance, the recommended storage condition for the humidity
sensor is 10°C to 40°C with 20% rH to 60% rH
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3 Pinning description
VDD
SCL
INT
SDA
GND
CS
6
5
4
3
2
1
Figure 2: Pinout (top view)
No Function Description Input/Output
1 VDD Positive supply voltage Supply
2 SCL I2C serial clock Input
3 INT Data ready output signal Output
4 SDA I2C / SPI: serial data input/output Input/Output
5 GND Negative supply voltage Supply
6 CS I2C/SPI enable/disable Input
Table 7: Pin description
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4 Application circuit
12
3
4 5
6
SCL
INT
SDA
VDD
100 nF
CS
GND
VDD
SCL
SDA
Rp Rp
VDD
Rp – Pull up resistor
I²C Bus configuration
SPI 3 wire to 4 wire configuration
SDA
MOSI
MISO
Rs
Rs – Series resistor
Figure 3: Electrical connection (top view)
A positive supply voltage is applied to the sensor through VDD pin and negative voltage to
GND. The decoupling capacitor of 100 nF in parallel is highly recommended to prevent the
voltage ripples on the VDD line. It should be placed as close as possible to the VDD pin.
The CS pin shall be connected to VDD_IO in order to enable the I2C communication interface. For SPI communication, the CS pin shall be connected to master side CS pin for active
start and stop SPI communication. The pull up resistors Rpfor I2C communication interface
should be connected parallel between supply voltage VDD and SCL and SDA pins.
Depending on the internal resistance of I2C pins at the master side, the pull up resistors
Rpcan be selected for proper rise and fall time of the digital signals. The 3-pin to 4-pin SPI
configuration can be configured as mentioned in the figure 3.
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5 Digital interface
Microcontroller
(Master)
R
p
R
p
Sensor
(Slave-1)
Sensor
(Slave-2)
+VDD
SCL
(serial clock)
SDA
(serial data)
Pull up resistors
The humidity sensor supports standard I2C (Inter-IC) bus protocol. Further information of
the I2C interface can be found at https://www.nxp.com/docs/en/user-guide/UM10204.pdf .
I2C is a serial 8-bit protocol with two-wire interface, which supports communication between
different ICs. For example, between the microcontroller and other peripheral devices.
5.1 General characteristics
A serial data line (SDA) and a serial clock line (SCL) are required for the communication
between the devices connected via I2C bus. Both SDA and SCL lines are bidirectional. The
output stages of devices connected to the bus must have an open-drain or open-collector.
Hence, the SDA and SCL lines are connected to a positive supply voltage via pull-up resistors. In I2C protocol, the communication is realized through master-slave principle. The
master device generates the clock pulse, a start command and a stop command for the data
transfer. Each connected device on the bus is addressable via a unique address. Master
and slave can act as a transmitter or a receiver depending upon whether the data needs to
be transmitted or received.
The sensor behaves like a slave device on the I2C bus
Figure 4: Master-slave concept
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5.2 SDA and SCL logic levels
SDA
SCL
START
Condition
STOP
Condition
Valid
data
Valid change
of data
The positive supply voltage to which SDA and SCL lines are pulled up (through pull-up
resistors), in turn determines the high level input for the slave devices. The sensor has
separate supply voltage VDD_IO for the SDA and SCL lines. The logic high ’1’ and logic low
’0’ levels for the SDA and SCL lines then depend on the VDD.
5.3 Communication phase
5.3.1 Idle state
During the idle state, the bus is free and both SDA and SCL lines are in logic high ’1’ state.
5.3.2 START(S) and STOP(P) condition
Data transfer on the bus starts with a START command, which is generated by the master.
A start condition is defined as a high-to-low transition on the SDA line while the SCL line is
held high. The bus is considered busy after the start condition.
Data transfer on the bus is terminated with a STOP command, which is also generated by
the master. A low-to-high transition on the SDA line, while the SCL line being high is defined
as a STOP condition. After the stop condition, the bus is again considered free and is in idle
state. Figure 5 shows the I2C bus START and STOP conditions.
Master can also send a REPEATED START (SR) command instead of STOP command.
REPEATED START condition is same as the START condition.
5.3.3 Data validity
After the start condition, one data bit is transmitted with each clock pulse. The transmitted
data is only valid when the SDA line data is stable (high or low) during the high period of the
clock pulse. High or low state of the data line can only change when the clock pulse is in low
state.
Figure 5: Data validity, START and STOP condition
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5.3.4 Byte format
R/W
7-bit slave address
LSBMSB
1 0 1 1 1 1 1
0 = Write
1 = Read
Data transmission on the SDA line is always done in bytes, with each byte being 8-bits long.
Data is transmitted with the most significant bit (MSB) followed by other bits.
If the slave cannot receive or transmit another complete byte of data, it can force the master
into a wait state by holding SCL LOW. Data transfer continues when the slave is ready which
is indicated by releasing the SCL pin.
5.3.5 Acknowledge (ACK) and No-Acknowledge (NAACK)
Each byte transmitted on the data line must follow an Acknowledge bit. The receiver (master or slave) generates an Acknowledge signal to indicate that the data byte was received
successfully and ready to receive next data byte.
After one byte is transmitted, the master generates an additional Acknowledge clock pulse
to continue the data transfer. The transmitter releases the SDA line during this clock pulse
so that the receiver can pull the SDA line to low state in such a way that the SDA line
remains stable low during the entire high period of the clock pulse. It is considered as an
Acknowledge signal.
If the receiver does not want to receive any further byte, it will not pull down the SDA line
and it remains in stable high state during the entire clock pulse. It is considered as a NoAcknowledge signal and the master can generate either a stop condition to terminate the
data transfer or a repeated start condition to initiate a new data transfer.
5.3.6 Slave address for the sensor
The slave address is transmitted after sending the start condition. Each device on the I2C
bus has a unique address. Master selects the slave by sending corresponding slave address
after the start condition. A slave address is a 7 bits long followed by a Read/Write bit.
Figure 6: Slave address format
The 7-bit slave address of the humidity sensor is 1011111b. The R/W bit determines the
data direction. ’0’ indicates a write operation (transmission from master to slave) and a ’1’
indicates a read operation (data request from slave).
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START
Condition
STOP
Condition
1...7 8 9 1...8
9
1...8 9
7-bit
Address
Read/
Write
ACK
Register
Address
ACK NACKData
7-bit slave address of the humidity sensor is 1011111b.
S
Slave address
+ Write
ACK
Register
address
DataACK ACK P
S
Slave address
+ Write
ACK
Register
address
Slave address
+ Read
ACK ACK
P
SR Data Data NACKACK
Transmission from master to slave
Transmission from slave to master
S
P
ACK
NACK
SR
START condition
STOP condition
Acknowledge
No acknowledge
Repeated start condition
a) I2C write: Master writing data to slave
b) I2C read: Master reading multiple data bytes from slave
5.3.7 Read/Write operation
Figure 7: Complete data transfer
Figure 8: Write and read operations of the sensor
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Once the slave-address and data direction bit is transmitted, the slave acknowledges the
master. The master transmits the next byte, which must be a register-address of the sensor.
It indicates the address of the register where data needs to be written to or read from.
After receiving the register address, the slave sends an Acknowledgement (ACK). If the
master is still writing to the slave (R/W bit = 0), it will transmit the data to slave in the same
direction. If the master wants to read from the addressed register (R/W bit =1), a repeated
start (SR) condition must be transmitted to the slave. Master acknowledges the slave after
receiving each data byte. If the master no longer wants to receive further data from the slave,
it would send No-Acknowledge (NACK). Afterwards, master can send a STOP condition to
terminate the data transfer. Figure 8 shows the writing and reading procedures between the
master and the slave device (sensor).
5.4 I2C Multiple bytes read operation
In order to read multiple bytes incrementing the register address, it is necessary to assert
the most significant bit of the sub-address field (output register address). The bit [7] must
be equal to 1 while bit [6-0] represents the address of the first register to be read. Here is
an example of how to read 4 bytes of data from output registers by requesting the data only
from 0x28.
• To read multiple bytes from the output registers 0x28 to 0x2B, the first register address
must be changed from 0x28 (b0010 1000) to 0xA8(b1010 1000 (MSB is changed from
’0’ to ’1’).
• After sending I2C address, start with reading from the register 0xA8 and request 4
bytes to read.
• The received 4 bytes gives the content from registers 0x28 to 0x2B.
There is no auto increment bit (enable/disable) implemented in the control register for multiple bytes of read.
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5.5 I2C timing parameters
Parameter Symbol
Standard mode Fast mode
Unit
Min Max Min Max
SCL clock frequency f
LOW period for SCL clock t
HIGH period for SCL clock t
LOW_SCL
HIGH_SCL
Hold time for START
condition
Setup time for (repeated)
START condition
SDA setup time t
SDA data hold time t
SU_SDA
HD_SDA
Setup time for STOP
condition
Bus free time between
STOP and START condition
Table 8: I2C timing parameters
SCL
t
HD_S
f
SCL
t
SU_P
t
BUF
0 100 0 400 kHz
4.7 1.3 µs
4.0 0.6 µs
4 0.6 µs
4.7 0.6 400 µs
250 100 ns
0 3.45 0 0.9 µs
4 0.6 µs
4.7 1.3 µs
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6 Serial Peripheral Interface (SPI)
µC
(SPI Master)
Sensor
(SPI Slave)
MOSI
MISO
CLK
CS
SDA
CLK
CS
Serial Peripheral Interface (SPI) is a synchronous serial communication bus system for the
communication between host microcontroller and other peripheral ICs such as ADCs, EEPROMs, sensors, etc. SPI is a full-duplex master-slave based interface allowing the communication to happen in both directions simultaneously. The data from the master or the slave
is synchronized either on the rising or falling edge of clock pulse. SPI can be either 4-wire or
3-wire interface. 4-wire interface consists of two signal lines and two data lines. All of these
bus lines are unidirectional.
1. Clock (SCL)
2. Chip select (CS)
3. Master out, slave in (MOSI)
4. Master in, slave out (MISO)
Figure 9: SPI Interface
Master generates the clock signal and is connected to all slave devices. Data transmission
between the master and salves is synchronized to the clock signal generated by the master.
One master can be connected to one or more slave devices. Each slave device is addressed
and controlled by the master via individual chip select (CS) signals. CS is controlled by the
master and is normally an active low signal.
MOSI and MISO are data lines. MOSI transmits data from the master to the slave. MISO
transmits data from the slave to the master.
The humidity sensor supports only 3-wire SPI communication.
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6.1 Data transfer
Communication begins when the master selects a slave device by pulling the CS line to
LOW. The clock and data lines (MOSI/MISO) are available for the selected slave device.
Data stored in the specific shift registers are exchanged synchronously between master and
the slave through MISO and MOSI lines. The data transmission is over when the chip select
line is pulled up to the HIGH state. 4-wire SPI uses both data lines for the synchronous data
exchange in both the direction. 3-wire SPI shares a single data line for the data transfer,
where the master and slave alternate their transmitter and receiver roles synchronously.
6.2 Communication modes
In SPI, the master can select the clock polarity (CPOL) and clock phase (CPHA). The CPOL
bit sets the polarity of the clock signal during the idle state. The CPHA bit selects the clock
phase. Depending on the CPHA bit, the rising or falling clock edge is used to sample and
shift the data. Depending on the CPOL and CPHA bit selection in the SPI control registers,
four SPI modes are available as per table9. In order to ensure proper communication,
master and the slave must be set to same communication modes.
CPOL CPHA Description
0 0 Clock polarity LOW in idle state; Data sampled on the rising clock edge
0 1 Clock polarity LOW in idle state; Data sampled on the falling clock edge
1 1 Clock polarity HIGH in idle state; Data sampled on the falling clock edge
1 0 Clock polarity HIGH in idle state; Data sampled on the rising clock edge
Table 9: SPI communication modes
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6.3 Sensor SPI Communication
7- bit register address
R/W
LSBMSB
A[6]
A[5] A[4] A[3] A[2] A[1] A[0]
0 = Write
1=Read
R/W A[6] A[5] A[4] A[3] A[2] A[1] A[0] DI[7] DI[6] DI[5] DI[4] DI[3] DI[2] DI[1] DI[0]
DO[7] DO[6] DO[5] DO[4] DO[3] DO[2] DO[1] DO[0]
CS
SCK
SDA
SAO
3-Wire SPI of this sensor uses following lines: SDA (data input, MOSI), SCL (serial clock)
and CS (chip select). For more information, please refer to pin description in the section 3.
CS is pulled LOW by the master at the start of communication. The SCL polarity is HIGH in
the idle state (CPOL = 1). The data lines (SDA & SAO) are sampled at the falling clock edge
and latched at the rising clock edge (CPHA = 1). Data is transmitted with MSB first and the
LSB last.
SPI read and write operations are completed in 2 or more bytes (multiple of 16 or more clock
pulses). Each block consists of a register address byte and a data byte. The first byte is the
register address. In the SPI communication, the register address is specified in the 7-bits
and the MSB of the register address is used as an SPI read/write bit (Figure10). When R/W
is ’0’, the data is written on to the sensor. When ’1’, the data is read from the sensor.
Figure 10: SPI register address
The next bytes of data, depending on the R/W bit, is either written to or read from the indexed
register. Figure11shows the complete SPI data transfer protocol.
The sensor supports 3-wire SPI communication uses SDA pin for both data
read and write operations. Communication protocol remains the same.
Figure 11: 4-wire SPI data transfer (CPOL = 1, CPHA = 1)
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6.3.1 SPI write operation
Register address
A[6]
A[5] A[4] A[3] A[2] A[1] A[0]
R/WStart
CS =
LOW
0
DI
[6]
DI
[5]
DI
[4]
DI
[3]
DI
[2]
DI
[1]
DI
[0]
DI
[7]
Data to be written
Stop
CS =
HIGH
Register address
A[6] A[5] A[4] A[3] A[2] A[1] A[0]
R/WStart
CS =
LOW
1
DO
[6]
DO
[5]
DO
[4]
DO
[3]
DO
[2]
DO
[1]
DO
[0]
DO
[7]
Data from indexed register
Stop
CS =
HIGH
The write operation starts with the CS = LOW and sending the 7-bit register address with
R/W bit = ’0’ (write command). Next byte is the data byte that is the data to be written to the
indexed register. Several write command pairs can be sent without raising the CS back to
HIGH. The operation is ended with CS = HIGH. The SPI write protocol is shown in the figure
12
.
Figure 12: SPI write protocol
6.3.2 SPI read operation
The read operation starts with the CS = LOW and sending the 7-bit register address with
R/W bit = ’1’ (read command). Data is sent out from the sensor through the SDA line. The
SPI read protocol is shown in the figure13.
Figure 13: SPI read protocol
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6.3.3 SPI timing parameters
Table10shows general SPI timing parameters. They are subject to VDD and the operating
temperature.
Parameter Symbol Min Max Unit
SCL clock frequency f
SCL
10
(1)
MHz
SPI clock cycle t
CS setup time t
CS hold time t
SDA input setup time t
SDA input hold time t
SAO valid output time t
SAO output hold time t
SAO output disable time t
SCL
SU_CS
h_CS
SU_SDA
h_SDA
v_SAO
h_SAO
dis_SAO
Table 10: SPI timing parameters
1. Recommended maximum SPI clock frequency for ODR ≤ 50 Hz is 8 MHz
100 ns
6 ns
6 ns
5 ns
15 ns
50 ns
9 ns
50 ns
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7 Quick start guide
Power up
Read Device ID register(0x0F)
Device ID = 0xBC ?
Communication successful
Communication failed
Yes
No
This chapter describes the sensor communication check and operation sequence of the
humidity sensor.
7.1 Communication check
After proper powering of the sensor, the first step is to check the communication of the sensor with an I2C or SPI digital interface. It can be verified by reading the DEVICE_ID register
(0x0F). If the value from the DEVICE_ID register (0x0F) is 0xBC, then communication from
master to sensor is successful.
Figure 14: Communication check
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Humidity sensor with integrated temperature sensor, Part Nr. 2525020210001
7.2 Sensor in operation
Sensor in power down
mode
Enable continuous operation mode
Enable BDU bit
Select output data rate: 1 Hz
CTRL_1(0x20)
If
DRDY signal is
available?
Enable DRDY_EN bit
Read data from output register
Compute the data
with calibration
registers
Compute the data using given
formula (Refer to chapter 9)
Yes
No
No data in output register
CTRL_3(0x22)
Output registers 0x28, 0x29, 0x2A,
0x2B
Output registers 0x28, 0x29, 0x2A,
0x2B
Read calibration registers
(Only once)
From registers 0x30 to 0x3F
Humidity value in %rH
Temperature value in °C
Output value
Steps can
be
performed
once
Steps can
be
performed
in loops
The following flow chart is an initialization example to operate the sensor in continuous mode
with output data rate of 1 Hz.
The initialization of the sensor can be performed by selecting the operation mode and output
data rate. After initialization of the sensor, it is recommended to check the availability of data
samples using DRDY signal at INT pin.
Figure 15: Sensor in operation
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8 Operating modes
Power down mode
One shot mode
Continuous Mode
Active mode
No Measurement
PD bit = 1
ODR = 01/10/11ODR = 00
Single measurement
of humidity and
temperature
One Shot bit = 1
The humidity sensor can be operated in two different modes. Operating modes can be selected by PD bit and ODR[1:0] bits in the CTRL_1 register(0x20) and ONE SHOT bit in the
CTRL_2 register(0x21).
• Continuous mode
• One shot mode
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Figure 16: Operating modes
By default after powering up, the sensor goes to power down mode. In power down mode,
all internal blocks are turned off to minimize the power consumption. After selecting one of
the two operating mode, the sensor is in active measurement state depending on the output
data rate.
8.1 Continuous mode
In the continuous mode, the sensor is in active measurement state for humidity and temperature values. The humidity and temperature values are available at a rate of selected output
data rate in the table 11.
Three possible output data rates in the continuous mode are mentioned in table 11.
ODR[1:0] Output data rate
00 One shot mode
01 1 Hz
10 7 Hz
11 12.5 Hz
Table 11: Output data rate
8.2 One shot mode
One shot mode can be used only when the humidity and temperature values are necessary
instead of continuous measurement value. ONE SHOT bit in the CTRL_2 register(0x21) is
used to start a new measurement. The humidity and temperature output values are acquired
and it is available in the output registers when the ONE SHOT bit is set to ’1’. After completion of a new measurement for humidity and temperature values, the ONE SHOT bit is set
to ’0’ automatically by the sensor.
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9 Sensor output data
9.1 Humidity sensor
The humidity sensor values are obtained from two 8-bit output registers H_OUT_L (0x28)
and H_OUT_H (0x29). These two 8-bit values are concatenated to form a 16-bit word, which
is represented in 2’s complement. The relative humidity value is calculated by linear interpolation method using values from humidity output registers H_OUT_L (0x28) and H_OUT_H
(0x29) along with calibration registers.
9.2 Steps to calculate humidity output value
Step 1 to step 6 can be performed only once
1. Read the coefficient values from the registers H0_rH_x2 (0x30) and H1_rH_x2 and
(0x31)
2. Divide the coefficients by 2 to get H0_rH and H1_rH:
(H0_rh_x2)/2 and (H1_rh_x2)/2
3. Read the values from register 0x36 and 0x37.
4. Concatenate 0x37 & 0x36 to obtain signed 16-bit value of H0_T0_OUT.
5. Read the values from register 0x3A and 0x3B.
6. Concatenate 0x3B & 0x3A to obtain signed 16-bit value of H1_T0_OUT.
7. Read the raw values from humidity output register 0x28 and 0x29.
8. Concatenate 0x29 & 0x28 to obtain 16-bit word of H_T_OUT.
9. Calculate the relative humidity value in rH % using below formula:
(H1_rH − H 0_rH ).(H_T _OUT − H0_T0_OU T )
Humidtiy =
(H1_T0_OU T − H0_T 0_OU T )
Humidity(% relative Humidity) = Humidity + H0_rH (2)
(1)
Equation 2 gives the humidity values in %rH. The software drivers must clip output values
exceeding the measurement range of the humidity sensor.
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WSEN_HIDS humidity sensor SDK is implemented with the above steps. It is
available in our website to download for free.
9.3 Temperature sensor
The temperature sensor values are obtained from two 8-bit output registers T_OUT_L (0x2A)
and T_OUT_H (0x2B). These two 8-bit values are concatenated to form a 16-bit word, which
is represented in 2’s complement.
The most significant bit (MSB) of the T_OUT_H register indicates the polarity of the temperature output value.
• If the sign bit is ’0’, then the value read is positive.
• If the sign bit is ’1’, then the value read is negative. In this case, take 2’s complement
of the entire word.
The temperature value is calculated by linear interpolation method using values from the
temperature output registers T_OUT_L (0x2A) and T_OUT_H (0x2B) along with calibration
registers.
9.4 Steps to compute temperature output value
Step 1 to step 13 can be performed only once
1. Read the coefficient value from the register T1_T0 (0x35) and store it in a variable
’tmp’.
2. Read the coefficient value from the registers T0_degC_x8 (0x32) and store it in a
variable ’buffer’.
3. Perform logic AND operation between ’tmp’ and 0x03 and left shift by 8 bits.
x = ((tmp & 0x03)<<8)
4. Perform logic OR operation between x and ’buffer’ to get T0_degC_x8.
T0_degC_x8 = x | buffer
5. Divide the coefficient by 8 to get T0_degC.
T0_degC = (T0_degC_x8)/8
6. Read the coefficient value from the registers T1_degC_x8 (0x33) and store it in a
variable ’buffer’.
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7. Perform logic AND operation between ’tmp’ and 0x0C and left shift by 6 bits.
y = ((tmp & 0x0C)<<6)
8. Perform logic OR operation between y and ’buffer’ to get T1_degC_x8.
T1_degC_x8 = y | buffer
9. Divide the coefficient by 8 to get T1_degC.
T1_degC = (T1_degC_x8)/8
10. Read the values from register 0x3C and 0x3D.
11. Concatenate 0x3D & 0x3C to obtain signed 16-bit value of T0_OUT.
12. Read the values from register 0x3E and 0x3F.
13. Concatenate 0x3F & 0x3E to obtain signed 16-bit value of T1_OUT.
14. Read the raw values from temperature output register 0x2A and 0x2B.
15. Concatenate 0x2B & 0x2A to obtain 16-bit word of T_OUT.
16. Calculate the temperature value in °C using below formula:
T emperature =
(T 1_degC − T 0_degC).(T _OU T − T 0_OUT)
(T 1_OUT − T 0_OU T )
T emperature(degree Celsius) = T emperature + T 0_degC (4)
Equation 4 gives the temperature values in °C.
WSEN_HIDS humidity sensor SDK is implemented with the above steps. It is
available in our website to download for free.
(3)
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10 Sensor register mapping
Register
Addr (Hex)
0x0F
0x10
0x20
0x21
0x22
0x27
0x28
0x29
0x2A
0x2B
0x30 - 0x3F
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type Comments
DEVICE_ID 1 0 1 1 1 1 0 0 R Device ID of the sensor
Average Reserved
CTRL_1 PD Reserved
CTRL_2 BOOT Reserved
CTRL_3 DRDY_H_L PP_OD Reserved
STATUS Reserved
1
AVG_T[2:0] AVG_H[2:0] R/W Internal average register
1
1
1
1
BDU ODR[1:0] R/W Control registers
Heater ONE SHOT R/W
DRDY_EN Reserved
1
R/W
H_DA T_DA R/W Status register
H_OUT_L H_OUT_L[7:0] R Output registers
H_OUT_H H_OUT_H[7:0] R
T_OUT_L T_OUT_L[7:0] R
T_OUT_H T_OUT_H[7:0] R
Calibration - R Calibration registers
10.1 Calibration Register mapping
Register
Addr (Hex)
0x30
0x31
0x32
0x33
0x35
0x36
0x37
0x3A
0x3B
0x3C
0x3D
0x3E
0x3F
Name Format Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
H0_rH_x2 u8 H_0[7:0] R
H1_rH_x2 u8 H_1[7:0] R
T0_degC_x8 u8 T_degC_0[7:0] R
T1_degC_x8 u8 T_degC_1[7:0] R
T1_T0 u2 Reserved
1
T_1[1:0] T_0[1:0] R
H0_T0_OUT_L[7:0] R
H0_T0_OUT s16
H0_T0_OUT_H[7:0] R
H1_T0_OUT_L[7:0] R
H1_T0_OUT s16
H1_T0_OUT_H[7:0] R
T0_OUT_L[7:0] R
T0_OUT s16
T0_OUT_H[7:0] R
T1_OUT_L[7:0] R
T1_OUT s16
T1_OUT_H[7:0] R
• u8: unsigned 8-bit
• s16: signed 16-bit using 2’s complement
• 10-bit T0 Temperature calibration value: 8-bit T_degC_0[7:0] from the register (0x32) and 2 bit T_0[1:0] from the register (0x35)
• 10-bit T1 Temperature calibration value: 8-bit T_degC_1[7:0] from the register (0x33) and 2 bit T_1[1:0] from the register (0x35)
1
The registers contents are loaded at boot procedure should not be changed. They contain
the factory calibration values and their content is automatically restored when the device is
powered up.
Writing to Reserved marked in the registers is not allowed. Writing to those
reserved marked bits may cause permanent damage to the sensor.
The content of the calibration registers should not be changed.
11 Register description
11.1 Device_ID (0x0F)
The value of this register gives the device ID: 0xBC (b10111100)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
1 0 1 1 1 1 0 0 R
Table 12: Device_ID register
11.2 Average (0x10)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
Reserved AVG_T[2:0] AVG_H[2:0]
Table 13: Average register
bits Description
R/W
AVG_T[2:0] Internal averaging of the samples for temperature output values
AVG_H[2:0] Internal averaging of the samples for humidity output values
Table 14: Average register description
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AVG_T[2:0] /
Number of samples
AVG_H[2:0]
000 2 4 0.08 1.14
001 4 8 0.05 0.54
010 8 16 0.04 0.37
1
011
100 32 64 0.02 0.11
101 64 128 0.015 0.009
110 128 256 0.01 0.05
111 256 512 0.007 0.03
Table 15: Number of internal averaging samples
1. Default configuration
averaged
(Temperature)
16 32 0.03 0.35
Number of samples
averaged (Humidity)
Noise
(°C)
Noise
(rh %)
11.3 CTRL_1 (0x20)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
PD
Reserved
BDU
Table 16: CTRL_1 register
bits Description
PD
BDU
Power down. By default, PD: 0 which is power down mode. PD: 1
Continuous mode for active measurement
Block data update. 0: Continuous update, 1: Output registers are not
updated until MSB and LSB is read
ODR[1:0] Output data rate of the humidity and temperature value
Table 17: CTRL_1 register description
11.3.1 Block data update (BDU)
ODR[1:0]
R/W
It is strongly recommended to set the BDU bit to ’1’ in the CTRL_1 register. By default the
BDU bit is ’0’ and the output registers are continuously updated. When the BDU bit is set
to ’1’ the content of the output registers is not updated until both MSB and LSB are read.
It avoids reading values related to different samples. As soon as the BDU is activated, the
output registers always contain the most recent output data produced by the sensor. If the
processor initiate the read function of the output registers T_OUT_L, T_OUT_H, H_OUT_L
and H_OUT_H, the update for that pair is blocked until both MSB and LSB of the data is read.
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ODR[1:0] Output data rate
00 One shot mode
01 1 Hz
10 7 Hz
11 12.5 Hz
Table 18: Output data rate
11.4 CTRL_2 (0x21)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
BOOT
bits Description
BOOT Reboot memory content. 0: normal mode, 1: reboot memory content
Heater Heater enable/disable. By default 0: disable, 1: enable
ONE SHOT
11.4.1 BOOT
The content of the internal registers stored in the flash memory block can be refreshed using
BOOT bit. After proper powering of the sensor, content of the flash memory is loaded to the
internal registers. When the BOOT bit is set to ’1’ the content of the internal flash memory
block is copied to the internal registers and also calibrates the sensor. Each sensor has
different factory trimmed values stored in the internal flash memory. The content in the flash
memory copied to internal registers permit good performance of the sensor. Therefore the
content of the internal registers should not be modified.
One shot mode enable. By default 0: conversion done, 1: start of new
Reserved
Table 19: CTRL_2 register
conversion
Table 20: CTRL_2 register description
Heater ONE SHOT R/W
11.4.2 Heater
In case of condensation on the sensor, heater can be turned on using Heater bit. The heating
of the sensor element will speed up the recovery time of the sensor after condensation. During active heating, the humidity and temperature output values should not be read. It is also
recommended that output values should not be read immediately after turning off the heater.
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Supply voltage (V) Current consumption (mA)
3.3 33
Table 21: Current consumption of the heater
11.5 CTRL_3 (0x22)
Bit 7 Bit 6
DRDY_H_L PP_OD
bits Description
DRDY_H_L
PP_OD
DRDY_EN
DRDY output signal on INT pin: Active high/low. Default value: 0 (0: active
Push pull or open drain selection on INT pin. Default value: 0 (0: Push-pull,
Data ready interrupt enable on INT pin. Default value: 0 (0: disabled, 1:
Bit 5 Bit 4 Bit 3
Reserved
Table 22: CTRL_3 register
high, 1: active low)
1: open drain)
Table 23: CTRL_3 register description
11.6 STATUS (0x27)
Bit 2 Bit 1 Bit 0 Type
DRDY_EN
enabled)
Reserved
R/W
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
Reserved
Table 24: STATUS register
bits Description
Humidity data available (0: no humidity data is available in the output
H_DA
T_DA
registers, 1: new humidity data is available in the output registers). As soon
as the H_OUT_H register is read, the H_DA bit is set to ’0’
Temperature data available (0: no temperature data is available in the
output registers, 1: new temperature data is available in the output
register). As soon as the T_OUT_H is read, the T_DA bit is set to ’0’
Table 25: STATUS register description
H_DA T_DA R
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11.7 H_OUT_L (0x28)
The value of the humidity output registers H_OUT_L(0x28) and H_OUT_H(0x29) is expressed in 16-bit resolution. Please refer chapter 9.1 to obtain the humidity value from
16-bit values of the output registers.
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
HUMIDITY[7:0]
Table 26: H_OUT_L register
bits Description
HUMIDITY[7:0] 8 least significant bits (LSB) of the humidity sensor output
Table 27: H_OUT_L register description
11.8 H_OUT_H (0x29)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
HUMIDITY[7:0]
Table 28: H_OUT_H register
R
R
bits Description
HUMIDITY[7:0] 8 most significant bits (MSB) of the humidity sensor output
Table 29: H_OUT_H register description
The software drivers must clip output values exceeding the measurement range of the humidity sensor.
11.9 T_OUT_L (0x2A)
The value of the temperature output registers T_OUT_L(0x2A) and T_OUT_H(0x0E) is expressed in 16-bit resolution. Please refer chapter 9.3 to obtain the temperature value from
16-bit values of the output registers.
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
TEMP[7:0]
Table 30: T_OUT_L register
R
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bits Description
TEMP[7:0] 8 least significant bits (LSB) of the temperature sensor output
Table 31: T_OUT_L register description
11.10 T_OUT_H (0x2B)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Type
TEMP[7:0]
Table 32: T_OUT_H register
bits Description
TEMP[7:0] 8 most significant bits (MSB) of the temperature sensor output
Table 33: T_OUT_H register description
R
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12 Handling humidity sensor
• It is important to understand that a humidity sensor is not a normal electronic component and needs to be handled with care.
• Chemical vapours at high concentration in combination with long exposure time may
offset the sensor reading.
• Furthermore it is recommended to store the sensors with temperature range of 10°C
and 40°C and humidity with a range of 20 rH% and 60 rH%.
• Long-term exposure to conditions outside normal humidity and temperature range,
especially at higher humidity range, may temporarily offset the output signal of humidity
sensor.
• After returning to the normal exposure conditions, the humidity output value will slowly
return to the calibration state by itself.
• If such cases happen, to recover the sensor accuracy to the normal state, it has to be
reconditioned to the following procedure :
1. Baking: 100°C to 110°C at 5 rH% for 12h
2. Re-hydration: 20°C to 30°C at 75 rH% for 12h
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13 Physical dimensions
2,0 ±0,1
0,9 ±0,1
1
2
3
4
0,315
2,0 ±0,1
5
6
0,35 ±0,05
1,5 ±0,05
0,3 ±0,05
1,0 ±0,05
1,5 ±0,05
Pin 1
Humidity
Port Hole
Exposed
Silicon Area
0,105
1,18
0,25
1,0
0,35
13.1 Module drawing
Figure 17: Sensor dimension [mm]
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13.2 Footprint
6
5
4
3
2
1
1,0
1,5
0,4
1,5
0,45
Figure 18: Recommended land pattern [mm] (top view)
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14 Manufacturing information
14.1 Moisture sensitivity level
The sensor product is categorized as JEDEC Moisture Sensitivity Level 3 (MSL3), which requires special handling.
More information regarding the MSL requirements can be found in the IPC/JEDEC J-STD-020
standard on www.jedec.org. More information about the handling, picking, shipping and the
usage of moisture/re-flow and/or process sensitive products can be found in the IPC/JEDEC
J-STD-033 standard on www.jedec.org.
14.2 Soldering
14.2.1 Reflow soldering
Attention must be paid on the thickness of the solder resist between the host PCB top
side and the modules bottom side. Only lead-free assembly is recommended according
to JEDEC J-STD020.
Profile feature Value
Preheat temperature Min T
Preheat temperature Max T
Preheat time from T
S Min
to T
S Max
S Min
S Max
t
S
150°C
200°C
60 - 120 seconds
Ramp-up rate (TLto TP) 3°C / second max.
Liquidous temperature T
Time tLmaintained above T
L
Peak package body temperature T
Time within 5°C of actual preak temperature t
L
t
L
P
P
217°C
60 - 150 seconds
see table below
20 - 30 seconds
Ramp-down Rate (TPto TL)* 6°C / second max.
Time 20°C to T
P
8 minutes max.
Table 34: Classification reflow soldering profile, Note: refer to IPC/JEDEC J-STD-020E
* In order to reduce residual stress on the sensor component, the recommended
ramp-down temperature slope should be lower than 3°C /s.
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Package thickness
Time
Temperature
T
p
t
p
t
L
t
S
T
s max
T
s min
TC –5°C
T
L
25
Time 25°C to Peak
Preheat Area
Max. Ramp Up Rate
Max. Ramp Down Rate
Volume mm
<350
3
Volume mm
350-2000
3
Volume mm
3
>2000
< 1.6mm 260°C 260°C 260°C
1.6mm - 2.5mm 260°C 250°C 245°C
> 2.5mm 250°C 245°C 245°C
Table 35: Package classification reflow temperature, PB-free assembly, Note: refer to IPC/-
JEDEC J-STD-020E
It is recommended to solder the sensor on the last re-flow cycle of the PCB. For solder paste
use a LFM-48W or Indium based SAC 305 alloy (Sn 96.5 / Ag 3.0 / Cu 0.5 / Indium 8.9HF /
Type 3 / 89%) type 3 or higher.
The reflow profile must be adjusted based on the thermal mass of the entire populated PCB,
heat transfer efficiency of the re-flow oven and the specific type of solder paste used. Based
on the specific process and PCB layout the optimal soldering profile must be adjusted and
verified. Other soldering methods (e.g. vapor phase) have not been verified and have to be
validated by the customer at their own risk. Rework is not recommended.
Figure 19: Reflow soldering profile
After reflow soldering, visually inspect the board to confirm proper alignment
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14.2.2 Cleaning and washing
Do not clean the product. Any residue cannot be easily removed by washing. Use a "no
clean" soldering paste and do not clean the board after soldering.
• Washing agents used during the production to clean the customer application might
damage or change the characteristics of the component. Washing agents may have a
negative effect on the long-term functionality of the product.
• Using a brush during the cleaning process may damage the component. Therefore,
we do not recommend using a brush during the PCB cleaning process
14.2.3 Potting and coating
• Potting material might shrink or expand during and after hardening. This might apply mechanical stress on the components, which can influence the characteristics of
the transfer function. In addition, potting material can close existing openings in the
housing. This can lead to a malfunction of the component. Thus, potting is not recommended.
• Conformal coating may affect the product performance. We do not recommend coating
the components.
14.2.4 Storage conditions
• A storage of Würth Elektronik eiSos products for longer than 12 months is not recommended. Within other effects, the terminals may suffer degradation, resulting in
bad solderability. Therefore, all products shall be used within the period of 12 months
based on the day of shipment.
• Do not expose the components to direct sunlight.
• The storage conditions in the original packaging are defined according to
DIN EN 61760 - 2.
• For a moisture sensitive component, the storage condition in the original packaging
is defined according to IPC/JEDEC-J-STD-033. It is also recommended to return the
component to the original moisture proof bag and reseal the moisture proof bag again.
14.2.5 Handling
• Violation of the technical product specifications such as exceeding the nominal rated
supply voltage, will void the warranty.
• Violation of the technical product specifications such as but not limited to exceeding
the absolute maximum ratings will void the conformance to regulatory requirements.
• ESD prevention methods need to be followed for manual handling and processing by
machinery.
• The edge castellation is designed and made for prototyping, i.e. hand soldering purposes only.
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• The applicable country regulations and specific environmental regulations must be observed.
• Do not disassemble the product. Evidence of tampering will void the warranty.
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15 Important notes
The following conditions apply to all goods within the sensors product range of Würth Elektronik eiSos GmbH & Co. KG:
15.1 General customer responsibility
Some goods within the product range of Würth Elektronik eiSos GmbH & Co. KG contain
statements regarding general suitability for certain application areas. These statements
about suitability are based on our knowledge and experience of typical requirements concerning the areas, serve as general guidance and cannot be estimated as binding statements
about the suitability for a customer application. The responsibility for the applicability and use
in a particular customer design is always solely within the authority of the customer. Due to
this fact, it is up to the customer to evaluate, where appropriate to investigate and to decide
whether the device with the specific product characteristics described in the product specification is valid and suitable for the respective customer application or not. Accordingly, the
customer is cautioned to verify that the documentation is current before placing orders.
15.2 Customer responsibility related to specific, in particular
safety-relevant applications
It has to be clearly pointed out that the possibility of a malfunction of electronic components
or failure before the end of the usual lifetime cannot be completely eliminated in the current
state of the art, even if the products are operated within the range of the specifications.
The same statement is valid for all software and software parts contained in or used with
or for products in the sensor product range of Würth Elektronik eiSos GmbH & Co. KG.
In certain customer applications requiring a high level of safety and especially in customer
applications in which the malfunction or failure of an electronic component could endanger
human life or health, it must be ensured by most advanced technological aid of suitable
design of the customer application that no injury or damage is caused to third parties in the
event of malfunction or failure of an electronic component.
15.3 Best care and attention
Any product-specific data sheets, manuals, application notes, PCN’s, warnings and cautions must be strictly observed in the most recent versions and matching to the products
revisions. This documents can be downloaded from the product specific sections on the
wireless connectivity and sensors homepage.
15.4 Customer support for product specifications
Some products within the product range may contain substances, which are subject to restrictions in certain jurisdictions in order to serve specific technical requirements. Necessary
information is available on request. In this case, the field sales engineer or the internal sales
person in charge should be contacted who will be happy to support in this matter.
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15.5 Product improvements
Due to constant product improvement, product specifications may change from time to time.
As a standard reporting procedure of the Product Change Notification (PCN) according to
the JEDEC-Standard, we inform about major changes. In case of further queries regarding
the PCN, the field sales engineer, the internal sales person or the technical support team in
charge should be contacted. The basic responsibility of the customer as per section
and
15.2
remains unaffected.
The sensor driver software ¨Sensor SDK¨ and it’s source codes are not subject to the Product Change Notification information process.
15.1
15.6 Product life cycle
Due to technical progress and economical evaluation we also reserve the right to discontinue production and delivery of products. As a standard reporting procedure of the Product
Termination Notification (PTN) according to the JEDEC-Standard we will inform at an early
stage about inevitable product discontinuance. According to this, we cannot ensure that all
products within our product range will always be available. Therefore, it needs to be verified
with the field sales engineer or the internal sales person in charge about the current product
availability expectancy before or when the product for application design-in disposal is considered. The approach named above does not apply in the case of individual agreements
deviating from the foregoing for customer-specific products.
15.7 Property rights
All the rights for contractual products produced by Würth Elektronik eiSos GmbH & Co. KG
on the basis of ideas, development contracts as well as models or templates that are subject
to copyright, patent or commercial protection supplied to the customer will remain with Würth
Elektronik eiSos GmbH & Co. KG. Würth Elektronik eiSos GmbH & Co. KG does not warrant
or represent that any license, either expressed or implied, is granted under any patent right,
copyright, mask work right, or other intellectual property right relating to any combination,
application, or process in which Würth Elektronik eiSos GmbH & Co. KG components or
services are used.
15.8 General terms and conditions
Unless otherwise agreed in individual contracts, all orders are subject to the current version of the "General Terms and Conditions of Würth Elektronik eiSos Group", last version
available at www.we-online.com.
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16 Legal notice
16.1 Exclusion of liability
Würth Elektronik eiSos GmbH & Co. KG considers the information in this document to be
correct at the time of publication. However, Würth Elektronik eiSos GmbH & Co. KG reserves the right to modify the information such as technical specifications or functions of
its products or discontinue the production of these products or the support of one of these
products without any written announcement or notification to customers. The customer must
make sure that the information used corresponds to the latest published information. Würth
Elektronik eiSos GmbH & Co. KG does not assume any liability for the use of its products.
Würth Elektronik eiSos GmbH & Co. KG does not grant licenses for its patent rights or for
any other of its intellectual property rights or third-party rights.
Notwithstanding anything above, Würth Elektronik eiSos GmbH & Co. KG makes no representations and/or warranties of any kind for the provided information related to their accuracy,
correctness, completeness, usage of the products and/or usability for customer applications.
Information published by Würth Elektronik eiSos GmbH & Co. KG regarding third-party products or services does not constitute a license to use such products or services or a warranty
or endorsement thereof.
16.2 Suitability in customer applications
The customer bears the responsibility for compliance of systems or units, in which Würth
Elektronik eiSos GmbH & Co. KG products are integrated, with applicable legal regulations.
Customer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements concerning its products, and any use of
Würth Elektronik eiSos GmbH & Co. KG components in its applications, notwithstanding
any applications-related in-formation or support that may be provided by Würth Elektronik eiSos GmbH & Co. KG. Customer represents and agrees that it has all the necessary
expertise to create and implement safeguards which anticipate dangerous consequences of
failures, monitor failures and their consequences lessen the likelihood of failures that might
cause harm and take appropriate remedial actions. The customer will fully indemnify Würth
Elektronik eiSos GmbH & Co. KG and its representatives against any damages arising out
of the use of any Würth Elektronik eiSos GmbH & Co. KG components in safety-critical
applications.
16.3 Usage restriction
Würth Elektronik eiSos GmbH & Co. KG products have been designed and developed for
usage in general electronic equipment only. This product is not authorized for use in equipment where a higher safety standard and reliability standard is especially required or where
a failure of the product is reasonably expected to cause severe personal injury or death,
unless the parties have executed an agreement specifically governing such use. Moreover,
Würth Elektronik eiSos GmbH & Co. KG products are neither designed nor intended for use
in areas such as military, aerospace, aviation, nuclear control, submarine, transportation
(automotive control, train control, ship control), transportation signal, disaster prevention,
medical, public information network etc. Würth Elektronik eiSos GmbH & Co. KG must be
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informed about the intent of such usage before the design-in stage. In addition, sufficient
reliability evaluation checks for safety must be performed on every electronic component,
which is used in electrical circuits that require high safety and reliability function or performance. By using Würth Elektronik eiSos GmbH & Co. KG products, the customer agrees to
these terms and conditions.
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17 License terms for Würth Elektronik eiSos
GmbH & Co. KG sensor product software and source
code
This License terms will take effect upon the purchase and usage of the Würth Elektronik
eiSos GmbH & Co. KG sensor products. You hereby agree that this license terms are applicable to the product and the incorporated software, firmware and source codes (collectively,
"Software") made available by Würth Elektronik eiSos in any form, including but not limited
to binary, executable or source code form.
The software included in any Würth Elektronik eiSos sensor product is purchased to you on
the condition that you accept the terms and conditions of this license terms. You agree to
comply with all provisions under this license terms.
17.1 Limited license
Würth Elektronik eiSos hereby grants you a limited, non-exclusive, non-transferable and
royalty-free license to use the software and under the conditions that will be set forth in this
license terms. You are free to use the provided software only in connection with one of the
products from Würth Elektronik eiSos to the extent described in this license terms.
You are entitled to change or alter the source code for the sole purpose of creating an application embedding the Würth Elektronik eiSos sensor product. The transfer of the source
code to third parties is allowed to the sole extent that the source code is used by such third
parties in connection with our product or another hardware provided by Würth Elektronik
eiSos under strict adherence of this license terms. Würth Elektronik eiSos will not assume
any liability for the usage of the incorporated software and the source code.
You are not entitled to transfer the source code in any form to third parties without prior written consent of Würth Elektronik eiSos.
You are not allowed to reproduce, translate, reverse engineer, decompile, disassemble or
create derivative works of the incorporated software and the source code in whole or in part.
No more extensive rights to use and exploit the products are granted to you.
17.2 Usage and obligations
The responsibility for the applicability and use of the Würth Elektronik eiSos sensor product
with the incorporated software in a particular customer design is always solely within the
authority of the customer. Due to this fact, it is up to you to evaluate and investigate, where
appropriate, and to decide whether the device with the specific product characteristics described in the product specification is valid and suitable for your respective application or
not.
You are responsible for using the Würth Elektronik eiSos sensor product with the incorporated software in compliance with all applicable product liability and product safety laws. You
acknowledge to minimize the risk of loss and harm to individuals and bear the risk for failure
leading to personal injury or death due to your usage of the product.
Würth Elektronik eiSos’ products are not authorized for use in safety-critical applications,
or where a failure of the product is reasonably expected to cause severe personal injury
or death. Moreover, Würth Elektronik eiSos’ products are neither designed nor intended for
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use in areas such as military, aerospace, aviation, nuclear control, submarine, transportation
(automotive control, train control, ship control), transportation signal, disaster prevention,
medical, public information network etc. You shall inform Würth Elektronik eiSos about the
intent of such usage before design-in stage. In certain customer applications requiring a very
high level of safety and in which the malfunction or failure of an electronic component could
endanger human life or health, you must ensure to have all necessary expertise in the safety
and regulatory ramifications of your applications. You acknowledge and agree that you are
solely responsible for all legal, regulatory and safety-related requirements concerning your
products and any use of Würth Elektronik eiSos’ products in such safety-critical applications, notwithstanding any applications-related information or support that may be provided by
Würth Elektronik eiSos. YOU SHALL INDEMNIFY WÜRTH ELEKTRONIK EISOS AGAINST
ANY DAMAGES ARISING OUT OF THE USE OF WÜRTH ELEKTRONIK EISOS’ PRODUCTS IN SUCH SAFETY-CRITICAL APPLICATIONS.
17.3 Ownership
The incorporated Software created by Würth Elektronik eiSos is and will remain the exclusive
property of Würth Elektronik eiSos.
17.4 Disclaimer of warranty
THE SOFTWARE AND IT’S SOURCE CODE IS PROVIDED "AS IS". YOU ACKNOWLEDGE THAT WÜRTH ELEKTRONIK EISOS MAKES NO REPRESENTATIONS AND WARRANTIES OF ANY KIND RELATED TO, BUT NOT LIMITED TO THE NON-INFRINGEMENT
OF THIRD PARTIES’ INTELLECTUAL PROPERTY RIGHTS OR THE MERCHANTABILITY OR FITNESS FOR YOUR INTENDED PURPOSE OR USAGE. WÜRTH ELEKTRONIK
EISOS DOES NOT WARRANT OR REPRESENT THAT ANY LICENSE, EITHER EXPRESS
OR IMPLIED, IS GRANTED UNDER ANY PATENT RIGHT, COPYRIGHT, MASK WORK
RIGHT, OR OTHER INTELLECTUAL PROPERTY RIGHT RELATING TO ANY COMBINATION, MACHINE, OR PROCESS IN WHICH THE WÜRTH ELEKTRONIK EISOS’ PRODUCT WITH THE INCORPORATED SOFTWARE IS USED. INFORMATION PUBLISHED BY
WÜRTH ELEKTRONIK EISOS REGARDING THIRD-PARTY PRODUCTS OR SERVICES
DOES NOT CONSTITUTE A LICENSE FROM WÜRTH ELEKTRONIK EISOS TO USE
SUCH PRODUCTS OR SERVICES OR A WARRANTY OR ENDORSEMENT THEREOF.
17.5 Limitation of liability
Any liability not expressly provided by Würth Elektronik eiSos shall be disclaimed.
You agree to hold us harmless from any third-party claims related to your usage of the Würth
Elektronik eiSos’ products with the incorporated software and source code. Würth Elektronik
eiSos disclaims any liability for any alteration, development created by you or your customers
as well as for any combination with other products.
17.6 Applicable law and jurisdiction
Applicable law to this license terms shall be the laws of the Federal Republic of Germany.
Any dispute, claim or controversy arising out of or relating to this license terms shall be
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resolved and finally settled by the court competent for the location of Würth Elektronik eiSos
registered office.
17.7 Severability clause
If a provision of this license terms are or becomes invalid, unenforceable or null and void,
this shall not affect the remaining provisions of the terms. The parties shall replace any such
provisions with new valid provisions that most closely approximate the purpose of the terms.
17.8 Miscellaneous
Würth Elektronik eiSos reserves the right at any time to change this terms at its own discretion. It is your responsibility to check at Würth Elektronik eiSos homepage for any updates.
Your continued usage of the products will be deemed as the acceptance of the change.
We recommend you to be updated about the status of new software, which is available on
our website or in our data sheet, and to implement new software in your device where appropriate.
By ordering a sensor product, you accept this license terms in all terms.
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List of Figures
1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Pinout (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3 Electrical connection (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4 Master-slave concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5 Data validity, START and STOP condition . . . . . . . . . . . . . . . . . . . . 14
6 Slave address format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7 Complete data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8 Write and read operations of the sensor . . . . . . . . . . . . . . . . . . . . . 16
9 SPI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
10 SPI register address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
11 4-wire SPI data transfer (CPOL = 1, CPHA = 1) . . . . . . . . . . . . . . . . . 21
12 SPI write protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
13 SPI read protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
14 Communication check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
15 Sensor in operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
16 Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
17 Sensor dimension [mm] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
18 Recommended land pattern [mm] (top view) . . . . . . . . . . . . . . . . . . . 41
19 Reflow soldering profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
List of Tables
1 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Humidity sensor specification . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Temperature sensor specification . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 Electrical specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5 Absolute maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8 I2C timing parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9 SPI communication modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
10 SPI timing parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
11 Output data rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
12 Device_ID register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
13 Average register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
14 Average register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
15 Number of internal averaging samples . . . . . . . . . . . . . . . . . . . . . . 34
16 CTRL_1 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
17 CTRL_1 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
18 Output data rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
19 CTRL_2 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
20 CTRL_2 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
21 Current consumption of the heater . . . . . . . . . . . . . . . . . . . . . . . . 36
22 CTRL_3 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
23 CTRL_3 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
24 STATUS register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Humidity sensor with integrated temperature sensor, Part Nr. 2525020210001
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25 STATUS register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
26 H_OUT_L register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
27 H_OUT_L register description . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
28 H_OUT_H register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
29 H_OUT_H register description . . . . . . . . . . . . . . . . . . . . . . . . . . 37
30 T_OUT_L register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
31 T_OUT_L register description . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
32 T_OUT_H register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
33 T_OUT_H register description . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
34 Classification reflow soldering profile, Note: refer to IPC/JEDEC J-STD-020E 42
35 Package classification reflow temperature, PB-free assembly, Note: refer to
IPC/JEDEC J-STD-020E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Humidity sensor with integrated temperature sensor, Part Nr. 2525020210001
User manual version 1.3 © December 2020
www.we-online.com/sensors 54
Monitoring
& Control
Automated Meter
Reading
Internet
of Things
more than you expect
Contact:
Würth Elektronik eiSos GmbH & Co. KG
Division Wireless Connectivity & Sensors
Max-Eyth-Straße 1
74638 Waldenburg
Germany
Tel.: +49 651 99355-0
Fax.: +49 651 99355-69
www.we-online.com/wireless-connectivity
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