In the sensor industry, force, temperature, and flow are among the most widely used sensors. In today's fast-paced society, due to the rapid development of science and engineering technology, the monitoring of classical physical quantities in various industry applications has become more frequent and has more diverse application requirements than ever before.
This article analyzes the technology, applications, and products of piezoresistive pressure sensors and shares some related principles and concepts.
pressure sensor
In measurement, "pressure" is equivalent to "pressure intensity" in physics, an important parameter reflecting the state of matter. Pressure measurement includes gauge pressure, absolute pressure, negative pressure, and vacuum. In industry, most pressure readings are 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 sensors can be classified into piezoresistive pressure sensors, piezoelectric pressure sensors, piezomagnetic pressure sensors, capacitive pressure sensors, Hall effect pressure gauges, etc., based on their working principles.
Piezoresistive pressure sensor
Semiconductor strain gauge sensors are known as piezoresistive pressure sensors in practical applications. Early piezoresistive pressure sensors were made by attaching semiconductor strain gauges to an elastic body. In the late 1970s, a diffused piezoresistive pressure sensor was developed, integrating a peripherally fixed force-sensitive resistor and a silicon film. This overcame the shortcomings of bonding, such as hysteresis, creep, low natural frequency, and integration difficulties. Furthermore, the strain gauge strip and circuits for error compensation and signal conditioning were integrated onto a single silicon chip.
The main characteristics of piezoresistive pressure sensors are their small size, light weight, and ease of integration. They also possess extremely high sensitivity and resolution, making them suitable for detecting minute pressures. However, because they are made of semiconductor silicon, they are sensitive to temperature; without temperature compensation, temperature errors can be significant.
Applications of piezoresistive pressure sensors
Due to its numerous advantages, piezoresistive pressure sensors have been widely used in aerospace, marine, petrochemical, medical equipment, meteorology, and military equipment.
In 2020, the COVID-19 pandemic spread globally, leading to an explosive surge in demand for medical equipment such as ventilators, oxygen concentrators, and blood pressure monitors. Piezoresistive pressure sensors are a key component in ventilators. In applications such as home-use ventilators, medical ventilators, and high-precision blood pressure monitors, piezoresistive pressure sensors experienced shortages and even stockouts.
Piezoresistive pressure sensor products
Piezoresistive pressure sensors are complex to manufacture and require stringent processing techniques. Currently, there are few domestically produced products on the market, with most being imported. Fortunately, while domestic products are few, they do exist, and in terms of performance parameters and technical capabilities, they are not inferior to imported products. Below, we provide an objective comparison and explanation of the technical parameters of two typical piezoresistive pressure sensors.
NXP MPXV5010DP
FATRI (Western Horse ) TYZV16-010-000-201
Pressure range
The 0~10kPa pressure range is a relatively small pressure measurement range. In practical applications, the range should be slightly larger than the actual pressure required. Products with this range are suitable for large commercial terminals, consumer electronics, and healthcare applications.
Operating temperature
The requirements for general industrial applications and integrated circuit systems are between -40 ℃ and 80 ℃. Both products have an operating temperature range of -40 ℃ to 125 ℃, which can meet the needs of most applications.
Zero-point output
Theoretically, under operating voltage excitation, the sensor output should be zero when unloaded. However, in reality, the sensor output is unstable when unloaded, resulting in a deviation range. The smaller this range, the better. Both products exhibit excellent zero-point output control range, providing relatively good reliability and stability.
Accuracy
The accuracy here refers to nonlinearity error. Nonlinearity is the percentage of the maximum deviation between the straight line determined by the output value under no-load and rated load and the measured curve under increased load, relative to the rated output value. The unit of nonlinearity is %FS , and nonlinearity error = range × nonlinearity. The maximum error of the two products is ± 5% , and in practical applications, it is usually within ± 5% . This accuracy is fully satisfactory for both consumer and commercial applications.
Overload pressure
Overload pressure is divided into two types: safe overload and ultimate overload. Safe overload means that the pressure sensor will not be damaged within this load range, but it cannot be overloaded for extended periods. Ultimate overload refers to the pressure sensor's critical load limit; exceeding this limit means the sensor will be damaged. From this indicator, it can be seen that the FATRI TYZV16 performs well in this aspect, surpassing the performance of imported brands.
Through parameter comparison, both products demonstrate excellent technical performance, with FATRI outperforming similar products in the overload metric. The two brands have different product lines and application markets, each with its own advantages in different areas.
NXP Semiconductors , formerly Philips Semiconductors, was founded in 1953 and is a globally renowned sensor brand. Its applications span multiple fields, including automotive electronics, home audio-visual systems, and healthcare.
FATRI (Xiamen) Technology Co., Ltd. is a rising star in the domestic sensor industry, possessing rich and solid product R&D and manufacturing capabilities in advanced materials, chip manufacturing, precision sensors (acceleration, temperature, pressure, etc.), and measurement equipment.
To develop any sensor well, the development and exploration of underlying core technologies are indispensable. The level of independent chip design and manufacturing capabilities directly affects the sensor's final performance and applicability. For example , according to publicly available information, FATRI has already acquired and mastered chip design and manufacturing technologies.
For sensor companies, the current and future market presents both opportunities and challenges, but more Chinese sensor companies are making great strides in the right direction. With the advancement of the Industrial Internet of Things and intelligent manufacturing, it is believed that even more outstanding domestic sensor companies and products will emerge.
