| 摘要 |
A semiconductor integrated circuit for communication has a reference oscillator with high frequency control accuracy. The oscillator has a capacitive load circuit including a plurality of fixed capacitance elements, a plurality of variable capacitance elements, and switch elements connected to the capacitance elements, and is configured such that it can oscillate at a frequency corresponding to a synthesized capacitance value of the fixed capacitance elements, variable capacitance elements, and external oscillation elements. Through a control circuit that can generate a signal for controlling the switch elements, a combination of the variable capacitance element and the fixed capacitance element can be selected, in which the slopes of the characteristics of the frequency to control voltage are equalized, and intervals between the respective characteristic lines are equalized by the synthesized capacitance value of the capacitive load circuit and the oscillation elements.
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