Experimental characterization of the reference channel of a differential pressure sensor using pressure shock waves

This article describes the experimental verification of the hydraulic time constant related to the reference channel of a micromachined differential p ressure sensor. A pressure shock wave is employed to apply a fast step impu lse of large amplitude to the device under test. The impulse response of th e device is captured. The hydraulic time constant of the system consisting of a channel of cross section 100 x 1 mum(2) and length 1.6 mm and a cavity of 700 x 700 x 1 mum(3) is found to be about 1.2 ms. The experimental resu lts are compared to predictions obtained by a number of analytical models a nd finite element simulations.