Data Sheet
The MiCS-4514 is a compact MOS sensor with two fully
independent sensing elements on one package.
The MiCS-4514 is a robust MEMS sensor for the
detection of pollution from automobile exhausts.
MiCS-4514
0278 rev 16
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
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
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-4514
0278 rev 16
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.
IMPORTANT PRECAUTIONS:
Read the following instructions carefully before using the MiCS-4514 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.
Page 2 of 5
Data Sheet
Power circuit and measurement circuit
Parameter
RED sensor/OX sensor Symbol Typ Min Max Unit
Heating power PH76/43 71/30 81/50 mW
Heating voltage VH2.4/1.7 - - V
Heating current IH32/26 - - mA
Heating resistance
at nominal power RH74/66 66/59 82/73 Ω
Rating Symbol Value / Range Unit
Maximum heater power dissipation PH
88 (RED sensor)/50 (OX
sensor) 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-4514
0278 rev 16
MiCS-4514 with measurement circuit (top view)
The two voltages measured on the load resistors are
directly linked to the resistances of the RED and OX sensors
respectively. RLOAD must be 820 Ωat the lowest in order
not to damage the sensitive layer.
MiCS-4514 with recommended supply circuit (top view)
RDRED is a 82 Ωand RDOX is a 133Ω. These resistors are
necessary to obtain the right temperatures on the two
independant heaters while using a single 5V power supply.
The resulting voltages are typically VHRED = 2.4V and
VHOX= 1.7V.
Page 3 of 5
Data Sheet
Package outline dimensions
The package is compatible with SMD assembly process.
Operating conditions
The heating power is typically 80 mW and 43
mW for the RED and OX sensor respectively.
Heating voltage is 2.35 and 1.7 V.
Heating current is 34 and 26 mA.
Heating resistance at nominal power is 74 and
66 ohm.
The resistance under air is 100 – 1500 kohm for
the RED sensor and 0.8 – 20 kohm for the OX
sensor.
MiCS-4514
0278 rev 16
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-4514 includes two sensor chips with independent heaters and sensitive layers. One sensor
chip detects oxidising gases (OX) and the other sensor detects reducing gases (RED). The internal
connections are shown above.
Pin Connection
A Rh1 OX
B Rs1 OX
C Rh1 RED
D Rs1 RED
E NC
F Rh2 RED
G Rs2 RED
H Rh2 OX
J Rs2 OX
K NC MiCS-4514 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-4514
0278 rev 16
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
