Crystal oscillator

Abstract

A crystal oscillator has characteristics in that reduction in oscillation margin makes the crystal oscillator less likely to oscillate, with the result that an amplitude of a voltage waveform at an input terminal of a CMOS inverter is reduced. A crystal oscillator of the invention has a detection circuit that outputs an alarm signal when the amplitude of the voltage waveform at the input terminal of the CMOS inverter becomes equal to or less than a predetermined specified value. As a result, it is possible to detect a change in the oscillation margin of the crystal oscillator without switching between circuits even after the crystal oscillator is incorporated in a device.

Dependencies are inferred from the claim text.