TGS 2612 pdf

FIGAROTENTATIVE PRODUCT INFORMATIONTGS 2612 - for the detection of Methane and LP GasFeatures:* Low power consumption* Similar sensitivity at same %LEL levelsfor both methane and LP gas* Long life and low cost* Uses simple electrical circuitApplications:* Residential LNG and LPG alarms* Portable combustible gas leak detectors* Detectors for LNG and LPGThe sensing element is comprised of a metal oxide semiconductor layer formedon an alumina substrate of a sensing chip together with an integrated heater.In the presence of a detectable gas, the sensor's conductivity increasesdepending on the gas concentration in the air. A simple electrical circuit canconvert the change in conductivity to an output signal which corresponds to thegas concentration.The TGS 2612 has high sensitivity to methane, propane and butane, making itideal for LNG and LPG monitoring. Due to its low sensitivity to alcohol vapors(a typical interference gas in the residential environment), the sensor is ideal forconsumer market gas alarms.Due to miniaturization of the sensing chip, TGS 2612 requires a heater currentof only 56mA and the device is housed in a standard TO-5 package.The figure below represents typical sensitivity characteristics,all data having been gathered at standard test conditions (seereverse side of this sheet). The Y-axis is indicated as sensorresistance ratio (Rs/Ro) which is defined as follows:Rs = Sensor resistance in displayed gases atvarious concentrationsRo = Sensor resistance in 5000ppm of methaneSensitivity Characteristics:100The figure below represents typical temperature and humiditydependency characteristics. Again, the Y-axis is indicated assensor resistance ratio (Rs/Ro), defined as follows:Rs = Sensor resistance at 10%LEL of each gasat various temperatures/65%RHRo = Sensor resistance at 10%LEL of each gasat 20°C and 65% R.H.Temperature/Humidity Dependency:105000ppm Methane2100ppm Propane1800ppm Iso-butane10AirEthanolRs/RoRs/Ro11MethaneIso-ButanePropane0.1100 1000 10000 100000Gas concentration (ppm)65%RH0.1-20 -10 0 10 20 30 40 50Ambient temperature (˚C)IMPORTANT NOTE: OPERATING CONDITIONS IN WHICH FIGARO SENSORS ARE USED WILL VARY WITH EACH CUSTOMER’S SPECIFIC APPLICATIONS. FIGARO STRONGLYRECOMMENDS CONSULTING OUR TECHNICAL STAFF BEFORE DEPLOYING FIGARO SENSORS IN YOUR APPLICATION AND, IN PARTICULAR, WHEN CUSTOMER’S TARGET GASESARE NOT LISTED HEREIN. FIGARO CANNOT ASSUME ANY RESPONSIBILITY FOR ANY USE OF ITS SENSORS IN A PRODUCT OR APPLICATION FOR WHICH SENSOR HAS NOT BEENSPECIFICALLY TESTED BY FIGARO.

Basic Measuring Circuit:The sensor requires two voltage inputs:heater voltage (VH) and circuit voltage(VC). The heater voltage (VH) is appliedto the integrated heater in order tomaintain the sensing element at aspecific temperature which is optimalfor sensing. Circuit voltage (VC) isapplied to allow measurement of voltage(VRL) across a load resistor (RL) which isconnected in series with the sensor.A common power supply circuit can beused for both VC and VH to fulfill thesensor's electrical requirements. Thevalue of the load resistor (RL) should bechosen to optimize the alarm thresholdvalue, keeping power dissipation (PS)of the semiconductor below a limit of15mW. Power dissipation (PS) will behighest when the value of Rs is equal toRL on exposure to gas.Specifications (tentative):Structure and Dimensions:ModelnumberTGS 2612Sensingelement typeD1Top viewStandardTargetpackagegasesTO-5 metal canMethane, propane, iso-butaneTypicalStandard circuitconditionsdetection range1~25%LEL of each gasHeaterVoltage VH 5 . 0± 0.2V DC/ACCircuitvoltage VC 5 . 0± 0.2V DC/ACPs≤ 15mWLoadresistance RL Variable0.45kΩ min.Sensingelementø9.2±0.2ø8.1±0.2Side viewHeaterresistance RH approx.59Ω at room temp.12.4±1.0Heatercurrent IH 56± 5mAElectricalcharacteristicsunder standard testconditionsStandard testconditionsREV: 07/04Heater powerconsumptionSensorresistanceSensitivity(change ratio of Rs)Cross sensitivity(corresponding with10%LEL methane)Test gas conditionsCircuit conditionsConditioningbefore testperiodThe value of power dissipation (PS) canbe calculated by utilizing the followingformula:(VC - VRL) 2PS =RSPHRs280mWVH = 5.0V DC0.68~6.8kΩ in 5000ppm methane0.50 ~ 0.65Rs (9000ppm)Rs (3000ppm)≤25%LELpropane≤25%LELiso-butaneMethane, propane, & iso-butanea t 20± 2 ˚C, 65± 5%RHVC = 5. 0± 0.01V DCVH = 5. 0± 0.05V DC7 daysin airSensor resistance (Rs) is calculated witha measured value of VRL by using thefollowing formula:RS =VC - VRLVRLx RL90˚ø0.55±0.0543123.6±0.110.0±1.03.6±0.1FIGARO ENGINEERING INC.1-5-11 Senba-nishiMino, Osaka 562 JAPANTel.: (81) 72-728-2561Fax: (81) 72-728-0467email: figaro@figaro.co.jpBottom viewø5.1