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MiCS – 2610
O
3
Gas Sensor
This datasheet describes the use of the MiCS-2610 in ozone detection applications. The package and the
mode of operation described in this document target the detection of the oxidizing gas O
3
in indoor or
outdoor environments. Ozone is a hazardous gas, which can cause respiratory problems at
concentrations above 100 ppb.
Features:
•
•
•
•
•
•
•
Low heater current
Wide detection range
High sensitivity
Fast thermal response
Electro-Static Discharge protected
Miniature dimensions
High resistance to shocks and vibrations
This Preliminary Data Sheet accompanies MicroChemical Systems MiCS-2610 sensors for O
3
gas. Reproduction and distribution of this document is
restricted by MicroChemical Systems. The following specifications are subject to change to accommodate continuous improvement.
MiCS-2610 Preliminary Data Sheet Rev 2
Page 1 of 4
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Sensor Characteristics
Important Precautions:
Please read the following instructions carefully before using the MiCS-2610 sensor described in this
document to avoid erroneous readings and to prevent the device from permanent damage.
•
Tin oxide (SnO
2
) gas sensors require a relatively long warm up period before correct O
3
measurements can be taken. It is
important to follow the limits in the specifications (see Table 1) and to keep the sensor in the recommended powered operating
mode until the signal reaches a stable level. After exposing the sensor to high concentrations of O
3
, make sure the sensor is
given enough time to recover before taking new measurements.
The sensor must not be wave-soldered without protection or exposed to high concentrations of organic solvents or corrosive
gases in order to avoid poisoning the sensitive layer. Use humidified gas for testing and calibration.
Heater voltages above the specified maximum rating of 2.5 V will destroy the sensor. An increase of 0.5 V at 2.35 V causes an
increase of the heater temperature of about 100°C. The correct operating temperature is obtained by applying a heater voltage
of 2.35 ± 0.05 V.
We strongly recommend using the operating mode and measurement circuit described in this document and referring to the
heater voltage in the “Electric Specifications” section. Deviating from these procedures may produce varying results or damage
the sensor.
For any additional questions, please contact us at:
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•
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Operating Mode:
The recommended mode of operation is a constant voltage
mode. A heater voltage of V
H
= 2.35 V is applied. This
causes the temperature of the sensing resistor (R
S
) to
reach about 430°C.
Detection of the O
3
concentration is achieved
measuring the sensing resistor R
S
during operation.
by
Measurement Circuit:
Figure 2 shows the pin connections of the MiCS-2610
ozone sensor. A simple circuit to measure the O
3
concentration is proposed in Figure 3. The heating voltage
V
H
is applied to pins 3 and 1. A load resistor R
L
is
connected in series with R
S
to convert the resistance R
S
to
a voltage V
S
between pins 2 and 4. R
S
can then be
calculated by the following expression:
R
S
= R
L
/(V
CC
- V
S
)
⋅
V
S
Sensor Response:
The sensor response to O
3
in air is represented in Figure
1. The sensor resistance R
S
is normalized to the
resistance under 100 ppb of O
3
(R
100ppb
).
3
R
H
10
4
1
2
R
S
1
2
3
4
Pin Number
Heater Ground
Sensor Pin
Heater Power
Sensor Pin
Figure 2: Equivalent circuit (top view) of MiCS 2610.
R
S
/ R
100ppb
1
0.1
V
CC
Gas
Sensor
3 2
4 1
V
H
0.01
10
100
O
3
[ppb]
1000
R
L
V
S
GND
Figure 3: Measurement circuit for O
3
detection.
Figure 1: R
S
/ R
100ppb
as a function of gas concentration
at 50% RH and 25°C.
MiCS-2610 Preliminary Data Sheet Rev 2
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Electrical Specifications
Maximum Ratings:
Rating
Maximum Heater Voltage
Maximum Sensor Supply Voltage
Maximum Heater Power Dissipation
Maximum Sensor Power Dissipation
Relative Humidity Range
Ambient Operating Temperature
Storage Temperature Range
Storage Humidity Range
Table 1
Symbol
V
H
V
CC
P
H
P
S
R
H
T
amb
T
sto
RH
sto
15
0
-40
15
Value / Range
2.5
5
90
1
−
−
−
−
95
50
+70
95
Unit
V
V
mW
mW
%RH
°C
°C
%RH
Operating Conditions:
Parameter
Heating Voltage,
Heating Current,
Heating Power,
Table 2
[1]
[1]
Symbol
V
H
I
H
P
H
R
H
Typ
2.35
34
80
69
Min
2.30
28
65
66
Max
2.40
36
87
81
Unit
V
mA
mW
Heating Resistance,
Ω
Min and Max values for the heating power are obtained by combining V
H, min
. with R
H, max
and V
H, max
. with R
H, min
, respectively.
Sensitivity Characteristics:
Characteristic
O
3
Detection Range
Sensing Resistance at 50 ppm
Sensing Resistance at 100 ppm
Sensitivity Factor
Table 3
[2]
[2]
Symbol
FS
R
S
R
S
S
R
Typ
Min
10
Max
10000
200*
400*
4.0*
Unit
ppb
k
Ω
k
Ω
-
70*
140*
2.0*
20*
40*
1.5*
Sensitivity Factor S
R
is defined as R
S
at 100ppb of O
3
divided by R
S
at 50ppb of O
3
. Test conditions are 50±5 %RH and
25±2°C.
Values are subject to changes before the final datasheet is published.
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MiCS-2610 Preliminary Data Sheet Rev 2
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