At Sensors Expo 2017, Jim Brownell, sales manager for All Sensors, shows the progression of microelectromechanical system (MEMS) pressure sensing over the past 30+ years from his company’s perspective. Starting with the A or alpha package that was created in the early 1980s, a packaged element pressure sensor had two integral ports and six leads for attachment to a printed circuit board or connector. Designed for low pressure measurements, in 1980, that meant 1 psi applications. Depending on how it was mounted, it occupied a 0.480 x 0.800 or 0.800 x 1.080-inch footprint.
With lower pressure requirements from 1 to ½ to ¼ inch water pressure and even 1 mbar measurements – the equivalent of waving your hand back and forth in front of the sensor, in heating, ventilating and air conditioning (HVAC), medical airflow in respiratory analysis, the miniature side port package reduced the volume to about x0.5 x 0.570 x 0.282. The 1.42-gram unit accommodates smaller tubing and includes an amplifier to increase the sensor’s output from the millivolt level to a voltage level output to interface directly to an analog to digital (A/D) converter.
In the miniature front port package, pressures in the 100 psi+ range and customers’ requirements for smaller packaging and higher accuracy are addressed.
The latest miniature top hat series of packages include a single pressure port with through hole as well as surface mount packaging and digital outputs.
For barometric applications, where a pressure reading is made directly from the environment and does not need a pressure attachment, the surface mounted U4 package.
These packages and the products offered in them address industry requirements for measuring increasingly lower pressures in increasingly smaller packages with increasing levels of intelligence and high accuracy and resolution.