A solid state sensor to sense pressure includes a semiconductor substrate having a crystallographic design axis, and an odd number of identical inverter modules coupled in series to form a ring oscillator on the semiconductor substrate. Each inverter module includes a pair of structurally identical CMOS inverter stages. A logic input circuit starts oscillation of the ring oscillator and select a signal propagation path therein, either through CMOS inverter stage more affected by the induced mechanical stress or through CMOS inverter stages less affected by the pressure, using two logic command signals. The ring oscillator allows a reading of a frequency of oscillation based on the two logic command signals.