In the sensor industry, force, temperature, and flow sensors are the most widely used types of sensors. With the rapid development of science and engineering technology, there has been an increased frequency and demand for monitoring classical physical quantities in different application fields.
In measurement, "pressure" in physics, which is an important parameter that reflects the state of matter. In pressure measurement, there are gauge pressure, absolute pressure, negative pressure, and vacuum pressure. The pressure indicated in industry is mostly gauge pressure, which is the difference between absolute pressure and atmospheric pressure. Therefore, absolute pressure is the sum of gauge pressure and atmospheric pressure. If the measured pressure is lower than atmospheric pressure, it is called negative pressure or vacuum pressure.
The piezoresistive sensor is commonly known as the piezoresistive pressure sensor in practical applications. In the early days, piezoresistive pressure sensors were made by attaching semiconductor strain gauges to elastic bodies. In the late 1970s, a diffused type piezoresistive pressure sensor with a peripheral fixed force-sensitive resistor and a silicon film was developed. This overcame the drawbacks of lag, creep, low inherent frequency, and integration difficulty caused by gluing, and integrated the strain resistance strip, error compensation, signal conditioning, and other circuits on one silicon wafer.
The main characteristics of a piezoresistive pressure sensor are its small size, light weight, and ease of integration. It has high sensitivity and resolution and is suitable for detecting small pressures. However, as it is made of semiconductor silicon material, it is temperature-sensitive. If temperature compensation is not applied, the temperature error can be significant.
Applications of Piezoresistive Pressure Sensor
Piezoresistive pressure sensors have a series of advantages and are widely used in aerospace, navigation, petrochemicals, medical equipment, meteorology, military equipment, and other fields.
Piezoresistive Pressure Sensor Products
Piezoresistive pressure sensors have a complex manufacturing process, and the requirements for the manufacturing process of the sensor are strict. Currently, there are few domestically produced products on the market, and most of them are imported. Fortunately, although there are few domestically produced products, there are still some available. Here are two typical piezoresistive pressure sensors with their technical parameters for objective comparison and explanation.
In general, the industrial application and integrated circuit system requirements are between -40℃ and 80℃.
Under the excitation of the working voltage, the theoretical output of the sensor should be zero when unloaded. However, the actual output of the unloaded sensor is unstable, resulting in a deviation range. The smaller the deviation range, the better.
Overload pressure is divided into two types: safe overload and ultimate overload. Safe overload refers to the load that will not cause destructive damage to the pressure sensor within this load, but it cannot be overloaded for a long time. The other type is ultimate overload, which refers to the critical load of the pressure sensor. Exceeding the limit means that the sensor will be damaged.
The XDB308 pressure sensor adopts the international advanced piezoresistive sensor technology. It has a pressure range of 0-10kPa, an operating temperature range of -40℃~80℃, a zero output deviation range of within ±0.1mV/V, and a safe overload of up to 150%FS. It is widely used in the fields of medical equipment, air conditioning, industrial control, and other industries.