TPMS pressure sensor introduction: NPP301 and SM5420

Automobile Tire The tire pressure monitoring system (TPMS) is mainly used to automatically monitor the tire pressure in real time when the car is driving, and to alarm for tire leakage and low pressure. At present, the TPMS system has quickly become a basic equipment to avoid accidents, and more and more vehicles are equipped with this system. TPMS is mainly divided into two types, one is indirect TPMS (Wheel-Speed ​​Based TPMS). The other is direct TPMS (Pressure-Sensor Based TPMS). In July 2001, the U.S. Department of Transportation and the National Highway Safety Administration jointly evaluated the two existing TPMS systems. The evaluation report believes that direct TPMS is superior to indirect TPMS in terms of function and performance, making the development of direct TPMS a popular trend. TPMS pressure sensors are all based on MEMS technology, mainly silicon integrated capacitive pressure sensors (such as Freescale's MPXY8020, MPXY8040) and silicon piezoresistive pressure sensors (such as NPX1, NPX2 of General NovaSensor, SM5420 of SMI). Silicon piezoresistive pressure sensor uses high-precision semiconductor resistance strain gauge to form Wheatstone bridge as the force-electric conversion measurement circuit, and its measurement accuracy can reach 0.01-0.03%FS. Silicon piezoresistive pressure sensor (NPP301 and SM5420) is suitable for the measurement of most non-corrosive gases and dry air. Features Ultra-small size, ultra-low cost surface mounting (SO-8) structure, suitable for Automation Component mounting Working temperature: -40℃～125℃ Static accuracy <±0.2%FSO can provide 100, 200 and 700Kpa absolute pressure ranges, applications in automobile tire pressure detection, medical equipment, air conditioning equipment, cable leakage detection, pressure switches and controllers Portable barometers, altimeters and consumer instruments. NPP301 and SM5420 are both surface-mounted silicon pressure sensors, which use silicon-silicon welding technology and highly stable ultra-small piezoresistive chips sealed in plastic shells. The pin structure of the integrated circuit is adopted, which can be installed in small places, thus providing a cheap product for a large number of OEM users. Under constant voltage power supply, a voltage signal proportional to the input pressure is generated. Users can amplify it or increase its added value through the signal conditioning circuit to meet the needs of their own products. NPP301 and SM5420 characteristic parameters: Pressure range 0 ~ 100kPa ≈ 15, Psi 0 ~ 200kPa ≈ 30, Psi 0 ~ 700kPa ≈ 100Psi Overload 3X. Rated pressure Electrical performance (25℃) Power supply 3.0V Maximum 10V. DC input impedance 5000±20%Ω Output impedance 5000±20%Ω Environmental conditions Electrostatic damage (ESD) ＞10kv Working temperature -40～125℃ Physical characteristics Weight ≈0.10g Compatible media Clean, dry, non-corrosive gas Technical indicators (all test values ​​are relative to 22℃, 3V constant voltage power supply) Zero output ±10mV Full scale output 60±20mV Linearity ±0.20%FSO Hysteresis and repeatability ±0.10%FSO Zero temperature coefficient ±0.04%FSO／℃ Resistance temperature coefficient 0 .30%／℃Sensitivity temperature coefficient -0.20VV%FSO／℃Zero point thermal hysteresis ±0.10%FSOLong term stability ±0.20%FSODimensions Unit: mm (in) Selection Series Range Package Type NPP-301-100A100kPa (15Psi) SO-8 NPP-301-200A200kPa (30Psi) SO-8 NPP-301-700A700kPa (100Psi) SO-8 Note: 1. This series is only available in absolute pressure type.