A transducer array of micromachined ultrasonic transducer elements is connected to a microbeamformer. Driver circuits of the microbeamformer have a first output coupled to a first electrode of a respective transducer element and a second output coupled to a second electrode of the respective transducer element. The driver circuits apply first and second time varying voltage signals to the electrodes, with one voltage signal being time inverted relative to the other. The peak-to-peak voltage applied to the transducer element is 1.75 to 2.0 times the peak-to-peak voltage of either the first or the second time varying voltage signal.