LMM-H03 Mass Air FLow Sensor Product Description LMM-H03 is a thermodynamic sensing element for the bidirectional measurement of mass air flow in a well defined channel. It is dedicated for applications with high reliability requirements such as medical or industrial gas flow applications. Mounted directly within the flowing media the LMM- H03 is sensitive against the heat transfer on a micrometer scale. This heat transfer is detected by a micro-machined silicon device which is mounted on ceramic substrate defining the geometry of the sensing element. The functional principle of the LMM-H03 is a hot film anemometer, which is the thin film version of the hot wire anemometer. A thin film heating element Hot Film Anemometer Component (heater) is heated to a defined temperature difference with respect to the air. Highly reliable and long term stable At zero flow there is heat dissipation due to the thermal conductivity of the air. With applied flow the heat dissipation increases steadily with the flow rate. Bi-directional airflow measurement The sensing element can be operated at Constant Power and Constant Fast reaction time Voltage mode. However, it is recommended to operate LMM-H03 in the Manufactured described Constant Temperature Difference (CTD) mode. In the CTD mode the electronics detects any change of the thermal equilibrium very quickly according ISO TS16949 and compensates it by adjusting the power settings through the heaters. This Can be adapted to various flow allows a very reliable mass flow measurement with a very short time constant channel geometries which is in the order of milliseconds., Can be used for almost all kind of gases and volatile substances Features Highly reliable and long term stable Fast reaction time Can be adapted to various flow channel geometries Can be used for almost all kind of gases and volatile substances Applications Engine Control Industrial gas flow measurement Leak detection in pressurized air systems Spirometer SENSOR SOLUTIONS /// DATASHEET LMM-H03 REV01 09/2016 Page 1 LMM-H03 Mass Air Flow sensor Absolute Maximum Ratings Parameter Symbol Condition Min Typ Max Unit Storage Temperature T after bonding, with protected bond bads -40 +25 +125 C Store Storage Temperature T before bonding, unprotected bond bads +10 +25 +40 C Store Maximum Current I at now flow, +25 C ambient 20 mA max Operation Conditions Parameter Symbol Condition Min Typ Max Unit Operation Temperature T after bonding, with protected bond bads -40 +25 +125 C Store Heater Overtemperature T T = T - T 100 120 K Heater Heater Heater air Sensing Properties Parameter Symbol Condition Min Typ Max Unit Resistance R Pad 1+2, T = +25 C 1300 1700 2100 ATS1 Amb Ambient Temperature Sensor 1 Resistance Heater 1 RHeater1 Pad 3+4, TAmb = +25 C 40.0 45.0 50.0 Resistance Heater 2 R Pad 5+6, T = +25 C 40.0 45.0 50.0 Heater2 Amb Resistance R Pad 7+8, T = +25 C 1300 1700 2100 ATS2 Amb Ambient Temperature Sensor 2 Temperature Coefficient measurement at T = 0 C and T = +100 C 5500 6000 6500 ppm/K 1 2 R and R ATS Heater TCR Match measurement at T = 0 C and T = +100 C 100 ppm/K 1 2 SENSOR SOLUTIONS /// DATASHEET LMM-H03 REV01 09/2016 Page 2