At the device level, packaging for microelectromechanical (MEMS) sensors is often performed by an outsourced assembly and test (OSAT) company. The sensors could include accelerometers, gyroscopes, magnetometers and microphones as well as pressure, temperature, infrared, biomedical, chemical and gas sensors. The first level of chip packaging formats includes cavity land grid array (LGA), molded cavity LGA, cavity leadframe (LF) designs similar to semiconductor packaging.
Some applications, such as automotive, require more stringent device package protection, even at the device level. For example, Amkor Technology, a leading OSAT supplier, offers packaging that meets:
- Automotive Industry Action Group (AIAG) IATF 16949 certification
- Automotive Electronics Council (AEC) AEC-Q100 reliability
However, it takes even greater packaging design effort for a sensor that has to interface to harsh media. For example, sensors that measure the pressure in hydraulic systems are often packaged in a housing that has a welded stainless-steel diaphragm to isolate the MEMS sensor and its associated electronics. These designs use an O-ring to seal the unit and prevent fluid leakage. Recently, DunAn Sensing introduced its MO series that eliminates the O-ring and welding and yet is compliant with the International Organization for Standardization (ISO) ISO14903 standard for tightness of components and joints on refrigeration systems and heat pumps. With its harsh media compatibility, the sensor can address a variety of applications, including those in:
- Heat Pumps
- Refrigeration
- HVAC
- Compressors
- Valves
- Pneumatics
Pressure is not the only sensor measurement that requires special packaging for harsh environments. For example, measuring proximity in industrial applications takes special design effort to make the package rugged enough to survive. To meet these requirements, Rockwell Automation’s Allen-Bradley Division offers rugged full stainless-steel models of its 871FM metal flat pack inductive proximity sensors. This version provides Factor-1 equal sensing with weld field immunity for tough applications. International Electrotechnical Commission (IEC) 60529 IP67 and IP69K rated models are available as well to meet other harsh environmental requirements.
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