The present invention provides apparatus for measuring volumetric or mass flow of fluid. The package includes a carrier substrate having a top side, a MEMS chip mounted on the top side of the carrier substrate, and at least one chip component on or above the top side of the carrier substrate or embedded in the carrier substrate. A switch electrically connects or disconnects the power supply lines with each other. The members to are sealed with a plastic package. The transmission gate circuit opens and closes the line between the output terminal and input terminal of the amplification gate circuit.