MLX90247C

MLX90247C Thermopile w/NTC Thermistor Features and Benefits Solid state sensor High reliability Low cost, small size On chip temperature sensor Applications Non-Contact Temperature Sensing Differential Temperature Sensing Climate Control Ear, Temple Thermometers Household and Commercial Appliances Ordering Information Part No. MLX90247C Description Thermopile with 100K NTC Thermistor Functional Diagram Description The MLX90247C is a thermopile sensor IC which detects very small amounts of heat radiation. The sensor consists of a membrane with a thermopile on top of it. The hot junctions of the thermopile are positioned near the center of the membrane, the cold junctions above the bulk silicon edge. Due to the low thermal conductivity of the membrane, absorbed heat will cause the temperature to increase more at the center of the membrane than at the edge above the bulk. This temperature difference is converted to an electric potential by the thermo-electric effect in the thermopile junctions. No supply voltage is needed. The sensor IC is packaged together with a NTC chip thermistor for cold junction reference. The thermopile and thermistor are separate components, mounted in close proximity. The NTC thermistors have higher sensitivity at low temperatures than the standard PTC thermistors in the B and D models. The sensor and thermistor can be used independent of each other if desired, as the thermopile potential is floating. ϑ− MLX90247C Discrete Infrared Sensor IC Page 1 Rev 1.0 17/Feb/01 MLX90247C Thermopile w/NTC Thermistor MLX90247C Electrical Specifications DC Operating Parameters TA = -40 C to 150 C, (unless otherwise specified) o o Parameter Thermopile Resistance Sensitivity TC of Sensitivity Time constant Thermistor Value Thermal Coefficient NTC (1) Symbol Rtp S TCs T Rntc βntc Test Condition @298K sensor @298K black body @299K @298K @298K 0-50°C (1) Min 44 29 Typ 59.5 42 0.1 Max 75 55 30 105 4161 Unit kΩ µV/K %/K ms kΩ K 95 4120 100 4140 (1) Tolerance given between 15°C and 35°C. Typical value corresponds to a relative resistance change of –4.68%/°C. Definition of β is ∆lnR/∆(1/T) with T in K. (Naperian logarithm). Note: when measuring resistances with an ohm meter, please take care that the internal protection diodes, as indicated in the functional diagram below, are always reverse biased. ϑ− MLX90247C Absolute Maximum Ratings Parameter Operating temperature Storage temperature Soldering temperature Value -40 ~ 150 -40 ~ 150