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Abstract

A semiconductor integrated circuit device provided with an input terminal supplied with a reference frequency signal from outside of the device, a bandpass filter circuit coupled to the input terminal and outputting an internal reference frequency signal and a PLL circuit coupled to the bandpass filter circuit to receive the internal reference frequency signal. The input terminal is supplied with the reference frequency signal generated by a quartz oscillator or the like mounted on the exterior of the semiconductor integrated circuit device. In response to the signal supplied to the input terminal, the bandpass filter circuit restricts components in a bandwidth except for the frequency of the reference frequency signal, and thus supplies the reference signal to the PLL circuit. The PLL circuit operates by using the reference frequency signal as the reference signal.

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First Claim