Measuring Pressure in Compact Spaces with the SM30F Pressure Sensing Die

Silicon MEMS technology has long replaced mechanical sensors with elastic (polymer) membranes and has proven its worth in millions of applications, including ventilation technology (HVAC), as well as in medical and automotive industries. Their advantages lie in their compact size, stability, and cost-effectiveness.

AMSYS has been distributing pressure sensing dies and sensors from Silicon Microstructures, Inc. (SMI), now part of TE, for over 25 years. The complete range of sensors covers all pressure types and ranges. These include differential/relative pressure and absolute pressure sensing dies, the latter also designed for harsh environments. Notably, the back-side pressurized SM97A is available for 10, 20, and 50 bar applications.

The SM30F presented here is designed for measuring medium-range relative and differential pressures from under 5 psi to 150 psi (approximately 350 mbar to 10 bar). These chips are available with an open or closed measurement bridge and provide an output signal of typically 80 mV (30 psi and 150 psi versions) or even 90 mV (5, 15, and 80 psi variants).

From a pressure range of 15 psi onwards, these sensing dies exhibit a consistently low non-linearity of typically only ±0.1% of the span on both the front and back sides. This makes the SM30F ideal for back-side pressurization, where the medium comes into contact only with the rear side during relative pressure measurements. Since this side consists solely of silicon, the SM30F pressure sensing die is also well-suited for measuring conductive and mildly corrosive liquids.

AMSYS’ range of silicon pressure sensing dies is further complemented by the SM9520 differential pressure die for ultra-low pressures between 10 mbar and 100 mbar, as well as the ultra-compact SM5108E absolute pressure die for 30, 60, and 100 psi (2, 4, and 7 bar). Additionally, AMSYS offers particularly robust ceramic sensing dies, especially for higher pressure ranges. Given the complexity of selecting the optimal solution, consulting a sensor specialist is recommended to find the best fit for your specific application.