| 摘要 |
An oscillation circuit used in a semiconductor device such as a cell-based IC, and comprises: an inverting amplifier 10, which is constructed so that it is possible connect a crystal oscillator XL between its input and output terminals, and so that it is possible to adjust its gain by a control signal CNT; and a wave-shaping circuit 11 such as a Schmitt circuit that shapes the waveform of the oscillation signal output from the inverting amplifier 10. The inverting amplifier 10 includes a plurality of inverter circuits that can be operated selectively, wherein one or two or more inverter circuits that are selected from the plurality of inverter circuits function as an inverting amplifier. The gain of the inverting amplifier is adjusted by selecting inverter circuits according to a control signal CNT. Also, the wave-shaping circuit 11 is constructed so that it is possible to adjust the gain when shaping a waveform according to a control signal CNT to correspond with the gain adjustment of the inverting amplifier.
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