Data Sheet
The MiCS-6814 is a compact MOS sensor with three fully
independent sensing elements on one package.
The MiCS-6814 is a robust MEMS sensor for the
detection of pollution from automobile exhausts and for
agricultural/industrial odors.
MiCS-6814
1143 rev 8
SGX Sensortech, Courtils 1
CH-2035 Corcelles-Cormondrèche
Switzerland
www.sgxsensortech.com
For more information please contact:
info.em@sgxsensortech.com
Features
• Smallest footprint for compact designs
(5 x 7 x 1.55 mm)
• Robust MEMS sensor for harsh environments
• High-volume manufacturing for low-cost
applications
• Short lead-times
Detectable gases
• Carbon monoxide CO 1 – 1000ppm
• Nitrogen dioxide NO20.05 – 10ppm
• Ethanol C2H5OH 10 – 500ppm
• Hydrogen H21 – 1000ppm
• Ammonia NH31 – 500ppm
• Methane CH4>1000ppm
• Propane C3H8>1000ppm
• Iso-butane C4H10 >1000ppm
0.01
0.10
1.00
10.00
100.00
0.01 0.1 1 10 100
Concentration [ppm]
Rs/R0
Hydrogen
NO
NO2
RED sensor, continuous power ON, 25°C, 50% RH
OX sensor, continuous power ON, 25°C, 50% RH
0.01
0.10
1.00
10.00
0.1 1 10 100 1000 10000 100000
Concentration [ppm]
Rs/R0
CO
Ethanol
Hydrogen
Methane
Propane
Iso-butane
Ammonia
0.01
0.10
1.00
10.00
0.1 1 10 100 1000 10000 100000
Concentration [ppm]
Rs/R0
CO
Ethanol Hydrogen
Methane
Propane
Iso-butane
Ammonia
H2S
Page 1 of 5
0.0
0.1
1.0
10.0
1 10 100 1000 10000 100000
Concentration [ppm]
Rs/R0
Hydrogen
Ethanol
Ammonia
Propane
Iso-butane
NH3 sensor, continuous power ON, 25°C, 50% RH
Data Sheet
Performance RED sensor
Characteristic
RED sensor Symbol Typ Min Max Unit
Sensing resistance in air (see note 1) R0- 100 1500 kΩ
Typical CO detection range FS 1 1000 ppm
Sensitivity factor (see note 2) S60 - 1.2 50 -
Performance OX sensor
Characteristic
OX sensor Symbol Typ Min Max Unit
Sensing resistance in air (see note 1) R0- 0.8 20 kΩ
Typical NO2detection range FS 0.05 10 ppm
Sensitivity factor (see note 3) SR- 2 - -
MiCS-6814
1143 rev 8
Notes:
1. Sensing resistance in air R0is measured under controlled ambient conditions, i.e. synthetic air at 23
±5°C and 50 ± 10% RH for RED sensor and synthetic air at 23 ±5°C and ≤ 5% RH for OX sensor.
Sampling test.
2. Sensitivity factor is defined as Rs in air divided by Rs at 60 ppm CO. Test conditions are 23 ± 5°C and
50 ± 10% RH. Indicative values only. Sampling test.
3. Sensitivity factor is defined as Rs at 0.25 ppm NO2, divided by Rs in air. Test conditions are 23 ± 5°C
and ≤ 5% RH . Indicative values only. Sampling test.
4. Sensitivity factor is defined as Rs in air divided by Rs at 1 ppm of NH3. Test conditions are 23 ± 5°C
and 50 ± 10% RH. Indicative values only. Sampling test.
Page 2 of 5
Performance NH3 sensor
Characteristic
OX sensor Symbol Typ Min Max Unit
Sensing resistance in air (see note 1) R0- 10 1500 kΩ
Typical NH3detection range FS 1 300 ppm
Sensitivity factor (see note 4) SR- 1.5 15 -
Data Sheet
Power circuit and measurement circuit
Parameter
RED sensor/OX sensor/NH3 sensor Symbol Typ Min Max Unit
Heating power PH76/43/66 71/30/60 81/50/73 mW
Heating voltage VH2.4/1.7/2.2 - - V
Heating current IH32/26/30 - - mA
Heating resistance
at nominal power RH74/66/72 66/59/64 82/73/80 Ω
Rating Symbol Value / Range Unit
Maximum heater power dissipation PH88 mW
Maximum sensitive layer power dissipation Ps 8 mW
Voltage supplyHeating current Vsupply 4.9 – 5.1 V
Relative humidity range RH 5 – 95 %RH
Ambient operating temperature Tamb -30 – 85 °C
Storage temperature range Tsto -40 – 120 °C
Storage humidity range RHsto 5 - 95 %RH
MiCS-6814
1143 rev 8
MiCS-6814 with measurement circuit (top view)
The example above shows the principle to read a resistance
between 1 kOhms and 2MOhms with a 8bit A/D converter.
Depending on the application and on the precision of the
A/D converter, a single load resistor of 56 kOhms may be
sufficient. Rload must be 820 Ohms at the lowest in order
not to damage the sensitive layer.
MiCS-6814 with recommended supply circuit (top view)
R1 is 130 Ohms, R2 is 820 Ohms and R3 is 27 Ohms. These
resistors are necessary to obtain the right temperatures on
the three independent heaters while using a single 5 V
power supply. The resulting voltages are typically VhRED =
2.4 V, VhOX = 1.7 V and VhNH3 = 2.2 V.
Page 3 of 5
Data Sheet
Package outline dimensions
The package is compatible with SMD assembly process.
Operating conditions
MiCS-6814
1143 rev 8
Sensor configuration
The silicon gas sensor structure consists of an accurately micro machined diaphragm with an
embedded heating resistor and the sensing layer on top.
The MiCS-6814 includes three sensor chips with independent heaters and sensitive layers. One sensor
chip detects oxidising gases (OX) , the other sensor detects reducing gases (RED) and the other
detects NH3. The internal connections are shown above.
Pin Connection
ARs2
BRh1 RED, Rs1 RED
CRh1 NH3
DRs1 NH3
ERh2 NH3
FRs2 NH3
GRh2 RED
HRs2 RED
JRh1 OX, Rs1 OX
KRh2 OX
MiCS-6814 configuration (bottom view)
Page 4 of 5
Data Sheet
SGX Sensortech, Courtils 1
CH-2035 Corcelles-Cormondrèche
Switzerland
www.sgxsensortech.com
For more information please contact:
info.em@sgxsensortech.com
Power circuit
The two resistors (82 ohm for RED and 51+82
ohm for OX) are necessary to obtain the right
temperatures on the two independent heaters
while using a 5V power supply.
Packaging
The sensors are packaged in a tape and reel for
expedition.
The sensors are placed in a carrier type. The
dimensions of the cavity are 5.5 x 7.5 x 2.55 mm
(the tolerance is +/- 0.2 mm).
The outside dimension of the reel is either 178
+- mm (for a maximum of 700 sensors ) or 330
+ 0.25 / -4 mm (for a maximum of 2000
sensors).
MiCS-6814
1143 rev 8
Whilst SGX sensortech has taken care to ensure the accuracy of the information contained herein it accepts no responsibility for the consequences
of any use thereof and also reserves the right to change the specification of goods without notice. SGX sensortech accepts no liability beyond the set
out in its standard conditions of sale in respect of infringement of third party patents arising from the use of tubes or other devices in accordance
with information contained herein.
Page 5 of 5
IMPORTANT PRECAUTIONS:
Read the following instructions carefully before using the MiCS-6814 described here to avoid erroneous
readings and to prevent the device from permanent damage.
•The sensor must be reflow soldered in a neutral atmosphere, without soldering flux vapours.
•The sensor must not be exposed to high concentrations of organic solvents, silicone vapours or cigarette-
smoke in order to avoid poisoning the sensitive layer.
•Heater voltage above the specified maximum rating will destroy the sensor due to overheating.
•This sensor is to be placed in a filtered package that protects it against water and dust projections.
•SGX sensortech strongly recommends using ESD protection equipment to handle the sensor.
