A package for a MEMS device, the package comprising a MEMS transducer within a chamber of the package; and a package substrate, wherein an upper surface of the package substrate defines at least part of a surface of the chamber; wherein the package substrate comprises a plurality of metal layers, the package substrate further comprising at least a part of a filter circuit for filtering RF signals, wherein a first metal layer is provided in a first plane of the substrate and wherein a resistor of the filter circuit is provided in a plane below the first plane.