How has low pressure sensing changed?

At Sensors Expo 2019 in San Jose, CA, Jim Brownell, sales manager for All Sensors, explains how All Sensors fits into Amphenol Corporation since it was acquired last year. As one of the twelve companies in Amphenol’s Advanced Sensing Group, All Sensors continues its focus on low pressure sensing applications. Low pressure for microelectromechanical systems (MEMS) pressure sensors used to be 10 inches of water column, then it moved to 5 inches water column and most recently it is 1 inch water column. The 1 inch parts can be used down to 0.25 or even 0.1 inch water column for heating, ventilating and air conditioning (HVAC) applications and medical applications including ventilators, respirators, operating room anesthesia and spirometry.

Packaging size for these types of pressure sensors has also changed over the years. Twenty years ago the package size for the company’s first product was much larger (almost 600 square mm not including the leads) and was intended for connector or through-hole mounting on a printed circuit board (PCB). Within a few years, the form factor was reduced to a much smaller footprint. Today’s newest Compact (or D) Series package sizes can have less than a 100-mm footprint and use surface mount technology. While packaging sizes can changed, the earlier packaging types continue to be available for supply/replacement continuity and since they continue to offer the right functionality for many applications. For example, the TLAX Series that was introduced earlier this year addresses pressure ranges of 0.5 to 30 in. H₂O (differential and gauge) and 1 to 150 PSI (differential and gauge). Housed in the company’s initial Alpha or A package, the 4 – 20 mA output sensor targets 2-wire current loop applications and has digital compensation for zero, span and thermal effects. Some things and some remain the same.