Pressure sensors have been gaining some general visibility, as they are seen as probably the next big-volume sensor to go into cell phones. But most pressure sensors these days aren’t targeted at such consumer applications.
At the recent MEMS Executive Congress, I met with Merit Sensors, a maker of pressure sensors intended for harsher environments. We looked at one such application for a differential pressure sensor earlier this year. In that case, Sensata was putting their device into the highly-acidic automotive exhaust stream.
Merit addresses another medium that is also surprisingly corrosive: blood. While that’s not their only application, their approach to surviving such materials is to use what they call “back-side entry”: they build the delicate bits of the sensor on the top of the die and then flip it over and etch the port into the back of the die. That keeps the blood (or whatever) away from anything it could degrade. They claim that this allows them to be more cost-competitive than would be possible if they had to resort to more exotic packaging to solve the problem.
They recently released their TR series, a rugged device assembled on a ceramic PCB. They say that the eutectic soldering of the sensor die onto the substrate lets them handle pressure bursts up to three times the rated pressure limit. It’s available as absolute pressure or gage pressure (that is, the measured pressure as compared to local barometric pressure).
You can find out more about the TR series in their release.