A capacitive differential pressure sensor based on silicon bulk micromachining is presented. This sensor, which is part of a flow metering system, transforms the differential pressure delivered by a fluidic oscillator into capacitance variations. These variations are then converted by an ASIC into a digital output signal. The system specifications require the detection of differential pressures as low as 0.6 Pa, over a dynamic range of 10/sup 5/, with a common mode pressure varying from 0.1 to 1.6 MPa. Insensitivity to mechanical vibrations of 2 m/s/sup 2/, from 10 Hz to 150 Hz, is also required. Static and dynamic modelling, as well as experimental results, show that these specifications can be obtained.