Thermal mass flow sensor TFSC100

air

Model TFSC100 thermal flow sensor chips are developed for manufacturing of flow sensors (e.g., TFS2100 flow sensors from BCM SENSOR). As there is no any moving part in the TFSC100 chip, this sensor chip is suitable for measuring low flow rate of air or gases, and can provide stable and reliable signals to flow sensors. Flow measurement by this sensor chip is realized thanks to a thermal bridge which consists of four thermal resistors to form a full Wheatstone bridge circuit. These thermal resistors are made from platinum film on the chip through MEMS process. Based on dedicated design in the measuring circuit, the characteristics of the two thermal resistors away from the heater is the same as that of the other two near the heater. This enables the flow sensor chip TFSC100 working as a linear sensor chip. To understand how this sensor chip works, it is recommended to refer to the two schematic diagrams at the section of Working Principle in this datasheet. Although both gold and aluminum wires can be used for wire bonding, the gold wires are more recommended. This is because the gold wires can provide to this sensor chip with higher stability and higher resistance to corrosion and humidity conditions when this sensor chip measures the flow medium. In order to have protection to this sensor chip, there is a passivation layer on the top surface of the TFSC100 chip, which provides the chip with resistance to dusts and moisture.