MicroChemical
Systems
P RELIMINARY
D ATA
S HEET
MiCS-2610 Preliminary Data Sheet Rev 2
Page 2 of 4
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 (SnO2) gas sensors require a relatively long warm up period before correct O3 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 O3, 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:
Operating Mode:
The recommended mode of operation is a constant voltage
mode. A heater voltage of VH = 2.35 V is applied. This
causes the temperature of the sensing resistor (RS) to
reach about 430°C.
Detection
of
the
O3
concentration
is
achieved
by
measuring the sensing resistor RS during operation.
Sensor Response:
The sensor response to O3 in air is represented in Figure
1. The sensor resistance RS is normalized to the
resistance under 100 ppb of O3 (R100ppb).
Measurement Circuit:
Figure 2 shows the pin connections of the MiCS-2610
ozone sensor. A simple circuit to measure the O3
concentration is proposed in Figure 3. The heating voltage
VH is applied to pins 3 and 1. A load resistor RL is
connected in series with RS to convert the resistance RS to
a voltage VS between pins 2 and 4. RS can then be
calculated by the following expression:
RS = RL /(VCC - VS
)
⋅ V
S
Figure 1: RS / R100ppb as a function of gas concentration
at 50% RH and 25°C.
RS
1
4
2
3
RH
Pin Number
1
Heater Ground
2
Sensor Pin
3
Heater Power
4
Sensor Pin
Figure 2: Equivalent circuit (top view) of MiCS 2610.
Figure 3: Measurement circuit for O3 detection.
VS
VCC
VH
Gas
Sensor
RL
GND
1
4
3 2
0.01
0.1
1
10
10
100
1000
O3 [ppb]
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