An electronic filter circuit includes an electromechanical resonator that is mounted directly to the surface of a silicon integrated circuit, rather than being a surface mounted or leaded filter can on a circuit board. This filter circuit allows the integrated circuit electronic package to be significantly smaller than a conventional electromechanical resonator package. The electromechanical resonator may be protected during processing and during use with a protective cover that is made of a material such as titanium. The protective cover is attached to the integrated circuit chip.