An ultrasound transducer assembly (10) is disclosed comprising a plurality of transducer elements (32) for transmitting and receiving ultrasound waves (24) each having a substrate (40) and a flexible membrane (46) disposed in a distance from a substrate. An AC voltage control unit (56) is provided for controlling an AC voltage provided to each of the transducer elements, and a DC voltage control unit (60) for controlling a DC bias voltage provided to the transducer elements in order to bring the flexible membranes in a collapse mode into contact with the substrate. The DC voltage control unit is adapted to disconnect the DC bias voltage from the transducer elements temporarily during the operation of the ultrasound transducer assembly to limit the collapse mode.