Datasheet SGP41
Air Quality Sensor for VOC and NOx Measurements MOx based gas sensor for air quality applications
 Outstanding long-term stability and lifetime
 I2C interface with digital output signals
 Very small 6-pin DFN package: 2.44 x 2.44 x 0.85 mm3
 Low power consumption: 3.0 mA at 3.3 V
 Tape and reel packaged, reflow solderable
Product Summary
The SGP41 is a digital gas sensor designed for easy
integration into air purifiers or demand-controlled
ventilation systems. Sensirion’s CMOSens® technology
offers a complete, easy-to-use sensor system on a single
chip featuring a digital I2C interface and temperaturecontrolled micro hotplates, providing one VOC and one
NOx based indoor air quality signal. Both sensing element
and Gas Index Algorithm feature an unmatchedrobustness against contaminating gases present in real-world applications enabling a unique long-term stability
as well as low drift. The very small 2.44 x 2.44 x 0.85
mm3 DFN package enables applications in limited
spaces. Sensirion’s state-of-the-art production process
guarantees high reproducibility and reliability. Tape andreel packaging together with suitability for standard
SMD assembly processes make the SGP41
predestined for high-volume applications.

Figure 1 Functional block diagram of the SGP41.

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Table of Contents
1 Sensor Performance................................................................................................................................................................3
2 Specifications ..........................................................................................................................................................................5
2.1 Electrical Specifications .....................................................................................................................................................5
2.2 Timing Specifications .........................................................................................................................................................5
2.3 Recommended Operating and Storage Conditions ...........................................................................................................6
2.4 Absolute Minimum and Maximum Ratings .........................................................................................................................7
2.5 Interface Specifications ......................................................................................................................................................7
2.6 Environmental Stability ......................................................................................................................................................8
2.7 Material Contents ...............................................................................................................................................................8
3 Sensor Output Signal Description .........................................................................................................................................9
3.1 Conditioning .......................................................................................................................................................................9
3.2 Raw Signal Measurement ..................................................................................................................................................9
3.3 VOC and NOx Index Measurement ..................................................................................................................................10
3.4 Built-in Self-Test...............................................................................................................................................................11
3.5 Reading out The Sensor Serial Number ..........................................................................................................................11
3.6 Sensor Start-up Behavior .................................................................................................................................................11
4 Digital Interface Description .................................................................................................................................................12
4.1 General Considerations ...................................................................................................................................................12
4.2 I2C Address ......................................................................................................................................................................12
4.3 I2C Voltage Levels............................................................................................................................................................12
4.4 I2C Protocol Speed...........................................................................................................................................................12
4.5 I2C Sequences .................................................................................................................................................................12
4.6 Checksum Calculation .....................................................................................................................................................13
4.7 I2C Commands .................................................................................................................................................................13
5 Mechanical Specifications ....................................................................................................................................................18
5.1 Traceability.......................................................................................................................................................................18
5.2 Package Outline...............................................................................................................................................................18
5.3 Land Pattern ....................................................................................................................................................................19
5.4 Soldering Instructions ......................................................................................................................................................19
6 Ordering Information .............................................................................................................................................................20
6.1 Packaging Information .....................................................................................................................................................20www.sensirion.com

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1 Sensor Performance
Table 1 lists specifications characterizing the gas sensing performance. The SGP41 chip provides two digital raw signals which
are sensitive to most VOCs typically present in indoor environments and oxidizing gases such as NOx or O3, respectively. The
raw signals are proportional to the logarithm of the resistance of the sensing material. For the specifications given below, ethanol
in clean air has been used as proxy gas for typical VOC based indoor air events and NO2 in clean air has been used as proxygas for typical oxidizing gas based indoor air events.
Parameter

Conditions

Output signal
range2VOC Index, processed value from SRAW_VOC
NOx Index, processed value from SRAW_NOX
SRAW_VOC, digital raw value from VOC pixel
SRAW_NOX, digital raw value from NOx pixel
Ethanol in clean air
NO2 in clean air
Ethanol in clean air
NO2 in clean air
VOC Index

Measurement
range
Specified range
Device-to-device
variation4

Values1
Min.
1
1
0
0
0
0
500
50
–

Typ.
–
–
–
–
–
–
–
–
<±15

Max.
500
500
65’53565’5351’000’000
10’000
10’000650–<±15NOx Index

–

<±50

–

<±50
Repeatability4

VOC Index

–

<±5

–

<±5
NOx Index

–

<±5

–

<±5
Limit of detection5,6 Ethanol in 500 ppb of ethanol7 and 0 ppb of NO2 in –else clean air
NO2 in 500 ppb of ethanol7 in else clean air

Response time 63–

SRAW_VOC, changing concentration from 5’000 –to 10’000 ppb of ethanol at sampling interval of 1 s
SRAW_NOX, changing concentration from 150 to –300 ppb of NO2 at sampling interval of 1 s

–

<10

<50
or
<10
<20
or
<10
–

<250

–

–

Units
VOC Index points
NOx Index points
ticks3
ticks
ppb
ppb
ppb
ppb
VOC Index pointsor% m.v.
(the larger)
NOx Index pointsor% m.v.
(the larger)
VOC Index pointsor% m.v.
(the larger)
NOx Index pointsor% m.v.
(the larger)ppb
or% of concentration setpoint(the larger)ss

1 99 % of the sensors will be within the minimum–maximum tolerance. Typical tolerance refers to the mean of the distribution for ≥100 sensors.
2 Humidity compensated when actual humidity value is provided as input to the sensor (see section 3.2 Raw Signal Measurement).
3 Signal in ticks is proportional to the logarithm of the resistance of the sensing layer.

4 Evaluated using the calibration and test sequence according to the application note SGP41 – Testing Guide.

5 Limit of detection is defined as the minimum change of concentration required to obtain a raw signal change 3 times higher than the noise at the given concentration setpoint.
6 Parameter tested over simulated lifetime of 10 years in an indoor environment. Test conditions: continuous operation in 250 ppm of Decamethylcyclopentasiloxane (D5) for

200 h.
7 A concentration of 500 ppb of ethanol corresponds to the equivalent of a typical VOC background present in an application environment, e.g., a typical OEM device.

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Parameter

Conditions

Switch-on behavior Time until reliably detecting VOC or NOx events8
Time until specifications in this SRAW_VOC
table are met
VOC Index
SRAW_NOXNOx Index
Sensitivity6
SRAW_VOC, doubling VOC
Ethanol inconcentration in else clean air specified range
5’000 to 10’000
ppb of ethanol
SRAW_NOX, doubling NO2
NO2 in specified
concentration in else clean air range
150 to 300 ppb ofNO2
Sampling interval–

Values
Min.
–
–
–
–
–
–

Typ.
<60
<1
<1.5
<7
<6
−870

Max.
–
–
–
–
–
–

Units

−710

−870

−1’030ticks–+1’480

–

ticks

+950

+1’480+2’010

ticks

0.5

1

10

s

s
h
h
d
h
ticks

Table 1 Gas sensing specifications at 25 °C and 50 % RH in zero air (considered as clean air for indoor air quality applications) and a power
supply of VDD of 3.3 V.

Figure 2 and Figure 3 display the typical response of the VOC and NOx raw signals, respectively, of SGP41 to ethanol, NO2,
and O3 as a function of their concentrations in otherwise clean air and a background consisting of 500 ppb of H2 + 500 ppb of
ethanol.

Figure 2 Typical sensor response by the VOC signal to ethanol,
NO2, and O3 normalized to 500 ppb of H2 + 500 ppb of ethanol. Data
were recorded at 25 °C and 50 % RH and a power supply of VDD of
3.3 V.

Figure 3 Typical sensor response by the NOx signal to ethanol,
NO2, and O3 normalized to 500 ppb of H2 + 500 ppb of ethanol. Data
were recorded at 25 °C and 50 % RH and a power supply of VDD of
3.3 V.

8 Signal change during 60-s event of 5’000 to 10’000 ppb of ethanol or of 100 to 300 ppb of NO2 is three times larger than signal drift of SRAW_VOC or SRAW_NOX,

respectively, without this event during the same duration.

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2 Specifications
2.1 Electrical Specifications
Table 2 lists electrical specifications of the SGP41. Default conditions of 25 °C and 3.3 V supply voltage apply to values in thetable below, unless otherwise stated. The SGP41 supports both I2C “standard-mode” and “fast-mode” (see NXP I2C-bus
specification and user manual).

Parameter

ValuesSymbol Min.

Supply voltage, hotplate supply
voltage9

VDD,
VDDH

Idle current

IDD

Supply current during conditioning
mode10

Supply current during VOC+NOx
measurement mode10

Communication

–

Typ.

Max.

Unit

Comments

1.7

3.3

3.6

V

Minimal voltage must be guaranteed also for the
maximum supply current specified in this table.
VDD and VDDH must be connected to the same
power supply, see Figure 6.

–

34

105

A

The idle mode is activated after power-up, after
calling the sgp4x_turn_heater_off command, orafter a soft reset.

–

6.5

7.2

mA

Average current consumption while the sensor iscontinuously operated at VDD, VDDH = 1.8 V.

–

4.2

4.6

mA

Average current consumption while the sensor iscontinuously operated at VDD, VDDH = 3.3 V.

–

4.3

4.8

mA

Average current consumption while the sensor iscontinuously operated at VDD, VDDH = 1.8 V.

–

3.0

3.4

mA

Average current consumption while the sensor iscontinuously operated at VDD, VDDH = 3.3 V.

Digital 2-wire interface, I2C

Table 2 Electrical specifications.

2.2 Timing Specifications
Timings in Table 3 refer to the power up and reset of the ASIC part and do not reflect the usefulness of the readings.
Parameter

SymbolCondition

Min.

Typ.

Max.

Unit

Power-up timetPU

After hard reset, VDD ≥ VPOR

–

0.4

0.6

ms

Soft reset timetSR

After soft reset

–

0.4

0.6

ms

SCL clock frequency

fSCL

–

–

–

400

kHz

Table 3 System timing specifications.

9 Any supply voltage as defined by the min./max. range may be used for continuous operation of the sensor. The typical value specifies the supply voltage at which outgoing

quality control is performed.
10 Sending the sgp41_execute_conditioning and sgp41_measure_raw_signals command enables continuous operation of the sensor. A 20 % higher current is drawn during
5 ms on VDDH after sending either of the two commands.

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2.3 Recommended Operating and Storage Conditions
Gas Sensing Specifications as detailed in Table 1 are guaranteed only when the sensor is stored and operated under therecommended conditions as specified in Table 4 and displayed in Figure 4 and Figure 5. Prolonged exposure to conditions
outside these conditions may reduce sensor performance. The sensor must not be exposed towards condensing conditions (i.e.,>90 % relative humidity) at any time.
Condition

Parameter

Min.

Max.

Unit

Operating conditions

Relative humidity

0

90

% RH

Temperature

−10

50

°C

Humidity

1.5 (−13)

30 (+31)–90(the smaller)

g m−3 (°C dew point)or% RH

Temperature

−10

50

°C

Relative humidity

0

80

% RH

Temperature

5

30

°C

Operating conditions ofhumidity compensation

Storage conditions

Table 4 Recommended humidity and temperature conditions for storing and operating the SGP41. Dew point refers to maximum humidity
allowed at minimum and maximum temperature, respectively.

Figure 4 Recommended relative humidity and temperature for
operating the SGP41. Green area marks conditions for which
humidity compensation has been optimized. Additionally, gray areas
mark operating conditions without using the humidity compensation
feature.

Figure 5 Recommended relative humidity and temperature forstoring the SGP41.

To ensure an optimal performance of the SGP41, Handling and Assembly Instructions for SGPxx Gas Sensors as well as the
Design-in Guide for Integrating SGP4x Gas Sensors need to be followed.

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2.4 Absolute Minimum and Maximum Ratings
Stress levels beyond those listed in Table 5 may cause permanent damage to the device. Exposure to minimum/maximum
rating conditions for extended periods may affect sensor performance and reliability of the device.
Parameter

RatingSupply voltage VDD−0.3 to +3.6 V

Supply voltage VDDH

−0.3 to +3.6 V

Short-term storage temperature range11−40 to +70 °C

Operating temperature range−20 to +55 °C

Short-term storage humidity range12

0 to 80 % (non-condensing)Operating humidity range

0 to 90 % (non-condensing)

ESD HBM

2 kV

ESD CDM

500 V

Latch up, JESD78 Class II, 125 °C

100 mA

Table 5 Absolute minimum and maximum ratings.

2.5 Interface Specifications
The SGP41 comes in a 6-pin DFN package, see Table 6. Figure 6 shows a typical application circuit. The VDD pin must be
decoupled with an RC element. The required decoupling for VDDH depends on the power supply network connected to thesensor, a capacitor of 1 F is recommended. VDD and VDDH must be connected to one single supply VDD. The external pullup resistors (e.g., Rp = 10 k) are required to pull the SDA and SCL signal lines high. For dimensioning resistor sizes pleasetake bus capacity and communication frequency into account (see section 7.1 of NXP I2C-bus specification and user manual for
more details). It should be noted that pull-up resistors may be included in I/O circuits of microcontrollers. The die pad or center
pad is electrically connected to GND. Hence, electrical considerations do not impose constraints on the wiring of the die pad.
However, for mechanical stability it is recommended to solder the die pad to the PCB.
Pin

Name

Comments

1

VDD

Supply voltage

2

VSS

Ground3

SDA

Serial data, bidirectional

4n/aConnect to ground (no electrical function)

5

VDDH

Supply voltage, hotplate

6

SCL

Serial clock, bidirectional

Table 6 Pin assignment (transparent top view). Dashed lines are only visible from the bottom.

11 Short-term storage refers to temporary conditions during, e.g., transport.

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Figure 6 Typical application circuit.

2.6 Environmental Stability
The SGP41 has been qualified based on the JEDEC JESD47 qualification test method. The Moisture Sensitivity Level
classification of the SGP41 is MSL1, according to IPC/JEDEC J-STD-020. At the same time, it is recommended to further
process the sensors within 1 year after date of delivery. The SGP41 should not be exposed to bright illumination by either
sunlight or artificial light sources during operation.

2.7 Material Contents
The device is fully RoHS, REACH, Halogen-free, and WEEE compliant, e.g., free of Pb, Cd, and Hg.

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3 Sensor Output Signal Description
3.1 Conditioning
After each restart of the sensor or when the hotplates have been switched off, the sgp41_execute_conditioning command must
be called from idle mode before the master calls the first sgp41_measure_raw_signals command (Figure 7). The conditioningheats the hotplate of the NOx pixel to a different temperature compared to the measurement mode enabling a faster switch-on(as specified in Table 1) thereafter. It is recommended to execute the conditioning for 10 s, but 10 s must not be exceeded to
avoid damage to the sensing material. Thereafter, the VOC+NOx measurement mode can be entered by following the
instructions given in 3.2 Raw Signal Measurement. The conditioning command requires to send default input parameters (2words + respective CRC bytes).

Figure 7 Standard process flow for executing the conditioning of SGP41.

Optionally, the master may already read out the raw signal of the VOC pixel (SRAW_VOC) during conditioning (Figure 8) since
the hotplate of the VOC pixel will already be set to the temperature used in the VOC+NOx measurement mode. After calling thesgp41_execute_conditioning command and after a subsequent minimum waiting time of 50 ms, SRAW_VOC is returned as one
16-bit word followed by a CRC byte. The sgp41_execute_conditioning command can be called consecutively multiple times
during the conditioning period.

Figure 8 Optional process flow for executing the conditioning of SGP41 and reading out the VOC raw signal.

3.2 Raw Signal Measurement
Calling the sgp41_measure_raw_signals command launches/continues the VOC+NOx measurement mode. The first call of thiscommand should be performed after the conditioning (see 3.1 Conditioning). This command starts one measurement of the raw
signals of the VOC and the NOx pixel (SRAW_VOC, SRAW_NOX) which are returned after 50 ms. The two raw signal values inticks are provided as two 16-bit words each followed by one CRC byte (Figure 9). The raw signals in ticks are proportional eachto the logarithm of the corresponding sensor resistance. These tow signals are used as input for Sensirion’s Gas Index Algorithm
to provide processed VOC and NOx Indices (see section 3.3 VOC and NOx Index Measurement). In case the Gas Index Algorithm
is not used, discard the first measured value of each signal. Typically, a measurement is performed every second by calling thesgp41_measure_raw_signals command again every second without turning the heater off. To exit the VOC+NOx measurementmode, the master calls the sgp4x_turn_heater_off command which switches off the hotplates and puts the sensor in idle mode.
In order to avoid prolonged run-in of the NOx signal, it is recommended to keep the measurement running whenever possible.

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Figure 9 Process flow for performing a raw signal measurement with the SGP41. For enabling on-chip humidity
compensation, current relative humidity and temperature values have to be supplied as part of the measurement
command.

The SGP41 features an automatic on-chip humidity compensation of both raw signals. The feature remains disabled as long as
default values for both humidity and temperature are sent together with the sgp41_measure_raw_signals command. For
enabling the compensation, the measurement command includes two words (+ respective CRC bytes) where the first word
represents the relative humidity and the second one represents the temperature.

3.3 VOC and NOx Index Measurement

Figure 10 Schematic of the driver and Gas Index Algorithm implementation on a microcontroller.

For best performance in indoor-air-quality use cases, Sensirion recommends processing the (humidity-compensated) raw
signals SRAW_VOC and SRAW_NOX through Sensirion’s powerful Gas Index Algorithm. This algorithm (Figure 10)
automatically adapts its outputs to any indoor environment and maps all VOC and NOx events to a VOC (Figure 11) and NOx
Index (Figure 12) scale, respectively, ranging from 1 to 500 index points. In case of the VOC Index, a value of 100 refers to theaverage indoor gas composition over the past 24 h. While values between 100 and 500 indicate a deterioration, values between
1 and 100 inform about improvement of the VOC based air quality. In case of the NOx Index, the average condition is mapped
to a value of 1 and therefore, the NOx Index displays values between 2 and 500 when NOx events are present. The Gas Index
Algorithm is available on github (see SGP41 product page on Sensirion’s webpage). SGP41 raw signals need to be provided to
the Gas Index Algorithm at a sampling rate of 1 s.

Figure 11 Explanation of the VOC Index scale.

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Figure 12 Explanation of the NOx Index scale.

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3.4 Built-in Self-Test
With the sgp41_execute_self_test command, users can perform an on-chip self-test for, e.g., in-line or end-of-line production
testing. If this command is called when the sensor is in idle mode, the sensor returns to idle mode after the test (Figure 13). In
case this command is called during VOC+NOx measurement mode (i.e., after calling the sgp41_measure_raw_signals
command), the hotplate remains switched on thereafter. It is not recommended to call this command during conditioning mode
(i.e., after calling the sgp41_execute_conditioning command). After 320 ms, the master can read a fixed data pattern (1 word +CRC byte) to check if the test was successful or not.

Figure 13 Process flow for performing the built-in self-test.

3.5 Reading out The Sensor Serial Number
Every SGP41 sensor carries a unique serial number for identification purposes which is hard coded during sensor production.
This number can be read out by using the sgp4x_get_serial_number command at any time in idle mode (Figure 14). After 1 ms,
the chip responds with 3 words (each word followed by one CRC byte) which together constitute the serial number.

Figure 14 Process flow for reading out the serial number of the SGP41 sensor.

3.6 Sensor Start-up Behavior
The sensor starts powering-up after reaching the power-up threshold voltage of 1.7 V and enters idle mode after max. 0.6 ms.
In this state, the sensor is ready to receive commands from the master.

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4 Digital Interface Description
4.1 General Considerations
For detailed information about the I2C protocol itself and its detailed implementation, please, consult the document NXP I2C-bus
specification and user manual. All SGP41 commands consist of two bytes (16 bits). The commands must not be followed by a
CRC. Additionally, data sent to and returned from the sensor is transferred in packets of two bytes (16 bits) followed by a 1-byte(8 bit) CRC.

4.2 I2C Address
The sensor’s I2C address is 89 (decimal; hex.: 0x59). The I2C header is formed by the I2C address followed by a read or writebit.

4.3 I2C Voltage Levels
Input and output voltage levels are specified in section 6.1 of NXP I2C-bus specification and user manual. The sensor’s interface
is compatible with 1.7–3.6 V I2C bus voltage levels depending on the supply voltage level.

4.4 I2C Protocol Speed
The sensor supports I2C “standard-mode” and “fast-mode”, with a maximum clock frequency of 100 or 400 kHz, respectively.

4.5 I2C Sequences
The typical communication sequence between the I2C master (e.g., a microcontroller in a host device) and the sensor isdescribed as follows and visualized in Figure 15:
1. The sensor is powered up.
2. The I2C master periodically calls the measurement command and reads data in the following sequence:a. I2C master sends a measurement command.
b. I2C master waits until the measurement is finished either by waiting for the maximum execution time or by waiting for the
expected duration and then poll data until the read header is acknowledged by the sensor (expected durations are listed
in Table 8).
c. I2C master reads out the measurement result.

Figure 15 Possible I2C command sequences for communicating with the SGP41. Dark areas indicate that the sensor controls the SDA (data)line. First, the I2C master sends the write header writing a 16-bit command, potentially followed by two words of data with CRC bytes. For
reading the measured data, the I2C master sends the read header and receives one word of data with CRC byte in case of the built-in selftest and in case of conditioning or two words with CRC bytes in case of measuring the raw signals of the two pixels. In case of reading out
the serial number of the sensor, the master receives three words with CRC bytes.

With the acknowledgement of the measurement command, the SGP41 starts measuring. When the measurement is in progress,
no communication with the sensor is possible and the sensor aborts the communication with a NACK condition. After the sensor
has completed the measurement, the master can read the measurement results by sending an I2C read header. The sensor will
acknowledge the reception of the read header and responds with data. The response data length is listed in Table 8 and iswww.sensirion.com

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structured in data words, where one word consists of two bytes of data (most significant bit first) followed by a one-byte CRC
checksum. Each byte must be acknowledged by the master with an ACK condition for the sensor to continue sending data. If
the sensor does not receive an ACK from the master after any byte of data, it will not continue sending data.
After receiving the checksum for the last word of data, a NACK and STOP condition have to be sent (see Figure 15). The I2C
master can abort the read transfer with a NACK followed by a STOP condition after any data byte if it is not interested insubsequent data, e.g., the CRC byte or following data bytes, in order to save time. Note that the data cannot be read more thanonce, and access to data beyond the specified amount will return a pattern of high bits.

4.6 Checksum Calculation
The 8-bit CRC checksum transmitted after each data word is generated by the CRC algorithm according to the properties asstated in Table 7. The CRC covers the contents of the two previously transmitted data bytes.
Property

Value

Example code

Name

CRC-8

Width

8 bit

Protected Dataread and/or write data

Polynomial

0x31 (x8 + x5 + x4 + 1)

Initialization

0xFF

Reflect input

False

Reflect output

False

Final XOR

0x00

ExamplesCRC (0xBE 0xEF) = 0x92

uint8_t CalcCrc(uint8_t data[2]) {uint8_t crc = 0xFF;
for(int i = 0; i < 2; i++) {crc ^= data[i];for(uint8_t bit = 8; bit > 0; --bit) {if(crc & 0x80) {crc = (crc << 1) ^ 0x31u;} else {crc = (crc << 1);}}}
return crc;}

Table 7 Checksums are used for the 2-byte data packets only. The command codes themselves already contain a 3-bit CRC and therefore,a checksum must not be appended.

4.7 I2C Commands
The available measurement commands of the SGP41 are listed in Table 8.
CommandCommand hex.
code

Parameter length
including CRC[bytes]Response length
including CRC[bytes]Measurement duration
[ms]
Typ.

Max.

sgp41_execute_conditioning

0x26 0x12

6

3

45

50

sgp41_measure_raw_signals

0x26 0x19

6

6

45

50

sgp41_execute_self_test

0x28 0x0E

–

3

300

320

sgp4x_turn_heater_off

0x36 0x15

–

–

0.1

1

sgp4x_get_serial_number

0x36 0x82

–

9

0.1

1

Table 8 I2C commands available for SGP41.

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Conditioning
CommandCommand hex. code

Description

sgp41_execute_conditioning

0x26 0x12 0x80 0x00 0xA2 0x66
0x66 0x93

This command starts the conditioning, i.e., the VOC pixel will be
operated at the same temperature as it is by calling thesgp41_measure_raw_signals command while the NOx pixel will
be operated at a different temperature for conditioning. This
command returns only the measured raw signal of the VOC pixel
SRAW_VOC as 2 bytes (+ 1 CRC byte).

Table 9 Description of the I2C conditioning command.

Byte number

Description

Value

0, 1

two bytes

u16 unsigned integer directly provides the raw signal
SRAW_VOC in ticks which is proportional to the logarithm of theresistance of the sensing element.

2

CRC byte for bytes 0, 1–

Table 10 Returned values by the I2C conditioning command.

Measure Raw Signals
Command

Subcommand

Command hex. code

Description

sgp41_measure_raw_signals

Without humidity
compensation

0x26 0x19 0x80 0x00 0xA2
0x66 0x66 0x93

This command starts/continues the VOC+NOx
measurement
mode,
leaveshumidity
compensation disabled by sending the default
values (see Table 12) and returns the measured
raw signals SRAW_VOC and SRAW_NOX as 2x2
bytes (+ 1 CRC byte).

With humidity
compensation

0x26 0x19 0xXX 0xXX 0xXX
0xYY 0xYY 0xYY

In order to enable the humidity compensation, themaster has to specify the relative humidity 0xXX
0xXX 0xXX and temperature 0xYY 0xYY 0xYY
input (incl. corresponding CRC bytes) in the format
as given in Table 12.

Table 11 Description of the I2C measurement command.

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Relative Humidity
Value / %Conversion into ticks

Temperature
Hex. code

RH/ticks=RH/%×Value / °C

65'535100

Hex. code
T/ticks=(T/°C + 45)×65'535
175

Default50

0x80 0x00 + CRC 0xA2

25

0x66 0x66 + CRC 0x93

Minimum

00x00 0x00 + CRC 0x81

−45

0x00 0x00 + CRC 0x81

Maximum

100

0xFF 0xFF + CRC 0xAC

130

0xFF 0xFF + CRC 0xAC

Table 12 Conversion of relative humidity in % and temperature in °C into ticks as the input parameters of the measurement command. Note:
minimum and maximum values do not reflect the range of conditions for which the humidity compensation feature has been optimized (seeTable 4).

Byte number

Description

Value

0, 1

two bytes

u16 unsigned integer directly provides the raw signal
SRAW_VOC in ticks which is proportional to the logarithm of theresistance of the sensing element.

2

CRC byte for bytes 0, 1

–

3, 4

two bytes

u16 unsigned integer directly provides the raw signal
SRAW_NOX in ticks which is proportional to the logarithm of theresistance of the sensing element.

5

CRC byte for bytes 3, 4–

Table 13 Returned values by the I2C measurement command.

Built-in Self-Test
CommandCommand hex. code

Description

sgp41_execute_self_test

0x28 0x0E

This command triggers the built-in self-test checking for integrityof both hotplate and MOX material and returns the result of thistest as 2 bytes (+ 1 CRC byte).

Table 14 Description of the I2C built-in self-test command.

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Byte number

Description

Value

0, 1

two bytes

0xXX 0xYY: ignore most significant byte 0xXX. The four leastsignificant bits of the least significant byte 0xYY provide
information if the self-test has or has not passed for eachindividual pixel:
bit

3

2

1

0

ignoreignoreNOx pixel

VOC pixel

Possible results for each bit:0: all tests passed successfully
1: one or more tests have failed
2

CRC byte for bytes 0, 1–

Table 15 Returned values by the I2C built-in self-test command.

Turn Heater off and Return to Idle Mode
CommandCommand hex. code

Description

sgp4x_turn_heater_off

0x36 0x15

This command turns the hotplate off and stops the measurement.
Subsequently, the sensor enters the idle mode.

Table 16 Description of the I2C heater off command.

Read out The Sensor Serial Number
CommandCommand hex. code

Description

sgp4x_get_serial_number

0x36 0x82

This command provides the decimal serial number of the SGP41
chip by returning 3x2 bytes (+ 1 CRC byte).

Table 17 Description of the I2C get serial number command.

Byte number

Description

Value

0, 1

two bytes

First (i.e., most significant) and second byte of the serial number.

2

CRC byte for bytes 0, 1

–

3, 4

two bytes

Third and fourth byte of the serial number.

5

CRC byte for bytes 3, 4

–

6, 7

two bytes

Fifth and sixth (i.e., least significant) byte of the serial number.

8

CRC byte for bytes 6, 7–

Table 18 Returned values by the I2C get serial number command.

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Soft ResetCommandCommand hex. code

Description

soft_reset

0x00 0x06

This command is a general call resetting all devices connected tothe same I2C bus. The first byte refers to the general call address
and the second byte refers to the reset command. After calling
this command, the SGP41 will restart entering the idle mode.

Table 19 Description of the I2C general soft reset command.

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5 Mechanical Specifications
SGP41 sensors are provided in a DFN (dual flat no leads) package with an outline of 2.44 × 2.44× 0.85 mm3 and a terminal pitchof 0.8 mm. The sensor opening with a typical diameter of 0.8 mm is offset to the bottom right corner on the top side of the
package. The sensor chip is assembled on a Ni/Pd/Au plated copper lead frame. Sensor chip and lead frame are over-moldedby a black, epoxy-based mold compound. Please note that the side walls of the package are diced and therefore the lead frame
sidewall surfaces are not plated.

5.1 Traceability
All SGP41 sensors are laser marked for easy identification and traceability (Figure 16). The marking on the sensor top side
consists of a pin-1 indicator and three lines of text. The top line consists of the pin-1 indicator which is located in the top left
corner and the product name. The two lines at the bottom consist of 2 alphanumeric digits each. That code can be decoded by
Sensirion only and allows for tracking on batch level through production, calibration, and testing – and will be provided uponjustified request.
If viewed from below pin 1 is indicated by triangular shaped cut in the otherwise rectangular die pad. The dimensions of thetriangular cut are shown in Figure 17, right. The sensor opening on the top side is not recommended for optical alignment.

Figure 16 Top view of the SGP41
illustrating the laser marking.

5.2 Package Outline

Figure 17 Package outline drawing of the SGP41. Dimensions are given in millimeters.

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5.3 Land Pattern
Recommended land pattern of the SGP41 is shown in Figure 18. Pads on PCB are recommended to be non-solder mask
defined (NSMD). Recommended solder paste stencil thickness is 125–150 m.

Figure 18 Recommended land pattern.

5.4 Soldering Instructions
Standard reflow soldering ovens and “no clean” type 3 solder paste (as specified in IPC J-STD-005A) should be used forsoldering the SGP41. The sensors are designed to withstand a soldering profile according to IPC/JEDEC J-STD-020. Peaktemperatures of TP = 245 °C during up to tp = 30 s for Pb-free assembly in IR/Convection reflow ovens (see Figure 19) arerecommended. In addition, we also recommend a maximum ramp-down rate of <4 °C s−1. Vapor phase or manual soldering
should not be used in order to avoid damaging of the sensor. In case the PCB hosting the SGP41 chip passes through multiple
solder cycles, it is recommended to assemble the SGP41 during the last solder cycle. Board wash and ultrasonic cleaning should
be avoided. For general information (such as conformal coating), please also refer to the Handling and Assembly Instructionsfor SGPxx Gas Sensors.

Figure 19 Soldering profile according to JEDEC standard. Recommended
conditions are TP = 245°C and tP ≤ 30 s for Pb-free assembly, TL < 220°C
and tL < 150 s. Ramp-up rate <3°C s−1 and ramp-down rate <4°C s−1.

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6 Ordering Information
Use the part names and product numbers shown in the following table when ordering the SGP41 gas sensor and accessories.
For the latest product information and local distributors, visit www.sensirion.com.
Part Name

Description

Ordering size

Product Number

SGP41-D-R4

SGP41 sensor components as tape on reel

2’500 pcs

3.000.060

SEK-SVM4x Evaluation Kit

1 SVM41 PCB equipped with SGP41, an SHT40, and an
MCU; 1 USB cable; 1 jumper wire cable; direct humidity
compensated VOC and NOx Index output via UART or I2C
interfacewww.sensirion.com/my-sgp-ek

1 pc

3.000.630

Table 20 SGP41 ordering options.

6.1 Packaging Information

Figure 20 Technical drawing of the packaging tape with sensor orientation in tape. Header tape is to the right and trailer tape to the left
on this drawing. Dimensions are given in millimeters.

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Important Notices
Warning, Personal Injury
Do not use this product as safety or emergency stop devices or in any other application where failure of the product could result in personal
injury. Do not use this product for applications other than its intended and authorized use. Before installing, handling, using or servicing thisproduct, please consult the data sheet and application notes. Failure to comply with these instructions could result in death or serious injury.
If the Buyer shall purchase or use SENSIRION products for any unintended or unauthorized application, Buyer shall defend, indemnify and hold harmless
SENSIRION and its officers, employees, subsidiaries, affiliates and distributors against all claims, costs, damages and expenses, and reasonable attorneyfees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if SENSIRION shallbe allegedly negligent with respect to the design or the manufacture of the product.

ESD Precautions
The inherent design of this component causes it to be sensitive to electrostatic discharge (ESD). To prevent ESD-induced damage and/or degradation, takecustomary and statutory ESD precautions when handling this product. See application note “ESD, Latchup and EMC” for more information.

Warranty
SENSIRION warrants solely to the original purchaser of this product for a period of 12 months (one year) from the date of delivery that this product shall beof the quality, material and workmanship defined in SENSIRION’s published specifications of the product. Within such period, if proven to be defective,
SENSIRION shall repair and/or replace this product, in SENSIRION’s discretion, free of charge to the Buyer, provided that:• notice in writing describing the defects shall be given to SENSIRION within fourteen (14) days after their appearance;• such defects shall be found, to SENSIRION’s reasonable satisfaction, to have arisen from SENSIRION’s faulty design, material, or workmanship;• the defective product shall be returned to SENSIRION’s factory at the Buyer’s expense; and• the warranty period for any repaired or replaced product shall be limited to the unexpired portion of the original period.
This warranty does not apply to any equipment which has not been installed and used within the specifications recommended by SENSIRION for the intended
and proper use of the equipment. EXCEPT FOR THE WARRANTIES EXPRESSLY SET FORTH HEREIN, SENSIRION MAKES NO WARRANTIES, EITHER
EXPRESS OR IMPLIED, WITH RESPECT TO THE PRODUCT. ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION, WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE EXPRESSLY EXCLUDED AND DECLINED.
SENSIRION is only liable for defects of this product arising under the conditions of operation provided for in the data sheet and proper use of the goods.
SENSIRION explicitly disclaims all warranties, express or implied, for any period during which the goods are operated or stored not in accordance with thetechnical specifications.
SENSIRION does not assume any liability arising out of any application or use of any product or circuit and specifically disclaims any and all liability, including
without limitation consequential or incidental damages. All operating parameters, including without limitation recommended parameters, must be validated
for each customer’s applications by customer’s technical experts. Recommended parameters can and do vary in different applications.
SENSIRION reserves the right, without further notice, (i) to change the product specifications and/or the information in this document and (ii) to improvereliability, functions and design of this product.
Copyright© 2021, by SENSIRION.
CMOSens® is a trademark of Sensirion
All rights reserved

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Revision History
Date

VersionPage(s)Changes

December 2021

1.0

All

Initial release

Headquarters and Subsidiaries
Sensirion AG
Laubisruetistr. 50
CH-8712 Staefa ZH
Switzerland

Sensirion Inc., USA
phone: +1 312 690 5858
info-us@sensirion.com
www.sensirion.com

Sensirion Korea Co. Ltd.
phone: +82 31 337 7700~3
info-kr@sensirion.com
www.sensirion.com/kr

phone: +41 44 306 40 00
fax:+41 44 306 40 30
info@sensirion.com
www.sensirion.com

Sensirion Japan Co. Ltd.
phone: +81 3 3444 4940
info-jp@sensirion.com
www.sensirion.com/jp

Sensirion China Co. Ltd.
phone: +86 755 8252 1501
info-cn@sensirion.com
www.sensirion.com/cn

Sensirion Taiwan Co. Ltd
phone: +886 3 5506701
info@sensirion.com
www.sensirion.com

To find your local representative, please visit
http://www.sensirion.com/distributors

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