An oscillator drive circuit and a trim circuit are implemented inside an integrated circuit of a sensor. The drive circuit provides an oscillating drive signal at a resonant frequency to drive a movable mass of the sensor. The drive circuit includes a phase shift circuit having an input for receiving a first signal indicative of an oscillation of the movable mass and having an output. The phase shift circuit adds a phase shift component to the first signal and produces a second signal shifted in phase by the phase shift component. The trim circuit includes a first comparator for receiving the first signal, a second comparator for receiving the second signal, and a processing element. The processing element determines a phase lag between the first and second signals and produces trim code for use by the phase shift circuit, the trim code being configured to adjust the phase shift component.