P R E MicroChemical Systems L I M I N A R Y D A T A S H E E T MiCS – 2610 O3 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 O3 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 O3 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 P R E MicroChemical Systems L I M I N A R Y D A T A S H E E T 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: Measurement Circuit: 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. 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: Detection of the O3 concentration is achieved measuring the sensing resistor RS during operation. by RS = RL /(VCC - VS) ⋅ VS 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). Pin Number 3 2 RS RH 10 4 1 1 Heater Ground 2 Sensor Pin 3 Heater Power 4 Sensor Pin RS / R100ppb Figure 2: Equivalent circuit (top view) of MiCS 2610. 1 VCC Gas Sensor 0.1 3 2 VS 4 1 VH RL 0.01 10 100 O3 [ppb] 1000 GND Figure 1: RS / R100ppb as a function of gas concentration at 50% RH and 25°C. MiCS-2610 Preliminary Data Sheet Rev 2 Figure 3: Measurement circuit for O3 detection. Page 2 of 4 P R E MicroChemical Systems L I M I N A R Y D A T A S H E E T Electrical Specifications Maximum Ratings: Rating Symbol Value / Range Unit Maximum Heater Voltage VH 2.5 V Maximum Sensor Supply Voltage VCC 5 V Maximum Heater Power Dissipation PH 90 mW Maximum Sensor Power Dissipation PS 1 mW Relative Humidity Range RH Ambient Operating Temperature Tamb Storage Temperature Range Tsto Storage Humidity Range RHsto 15 − 95 %RH 0 − 50 °C -40 − +70 °C 15 − 95 %RH Table 1 Operating Conditions: Parameter Typ Min Max Unit Heating Voltage, VH 2.35 2.30 2.40 V Heating Current, IH 34 28 36 mA PH 80 65 87 mW RH 69 66 81 Ω Heating Power, Symbol [1] Heating Resistance, Table 2 [1] Min and Max values for the heating power are obtained by combining VH, min. with RH, max and VH, max. with RH, min, respectively. Sensitivity Characteristics: Characteristic Symbol Typ Min Max Unit O3 Detection Range FS 10 10000 ppb Sensing Resistance at 50 ppm RS 70* 20* 200* kΩ Sensing Resistance at 100 ppm RS 140* 40* 400* kΩ SR 2.0* 1.5* 4.0* - Sensitivity Factor [2] Table 3 [2] Sensitivity Factor SR is defined as RS at 100ppb of O3 divided by RS at 50ppb of O3. Test conditions are 50±5 %RH and 25±2°C. * Values are subject to changes before the final datasheet is published. MiCS-2610 Preliminary Data Sheet Rev 2 Page 3 of 4 P R E MicroChemical Systems L I M I N A R Y D A T A S H E E T Package Dimensions and Filter J H A B C I D K E Dimension Min [mm] Max [mm] A 9 9.15 C 5.75 5.85 D 0.6 0.9 B G 8.35 E F MiCS-2610 Preliminary Data Sheet Rev 2 Page 4 of 4 3.5 F 8.5 G 15 9.5 16 H 2.41 2.67 I 0.55 0.65 J 4.83 5.33 K 0.7 0.9