Patent ID: 6720837
Filing Date: 2004-04-13
Classification: H01L,H03B

Abstract:
A surface mounting crystal oscillator comprising:a container body having a recess; a crystal blank having one end held on a step formed on an inner wall of said recess and functioning as a crystal unit; an IC chip secured on a bottom of said recess, said IC chip having integrated therein a first and a second capacitor connected to one and the other ends of said crystal unit, respectively, to form a resonance circuit, and an oscillation amplifying element for amplifying an oscillation frequency depending on said resonance circuit and feeding back the amplified oscillation frequency; and a metal cover for sealing an opening face of said recess, wherein a first stray capacitance produced between said crystal blank and said IC chip is connected in parallel with said first capacitor, and a second stray capacitance produced between said crystal blank and said metal cover is connected in parallel with said second capacitor, and a first gap defined between said crystal blank and said IC chip, and a second gap defined between said crystal blank and said metal cover are set in accordance with a changing amount of the oscillation frequency due to a change in said first stray capacitance and said second stray capacitance in a direction in which a change in an equivalent series capacitance is reduced as viewed from said crystal unit, while maintaining a spacing between said IC chip and said metal cover constant.