An integrated circuit may include oscillator circuitry having a resonator formed from fin field-effect transistor (FinFET) devices. The resonator may include drive cells of alternating polarities and sense cells interposed between the drive cells. The resonator may be connected in a feedback loop within the oscillator circuitry. The oscillator circuitry may include an amplifier having an input coupled to the sense cells and an output coupled to the drive cells. The oscillator circuitry may also include a separate inductor and capacitor based oscillator, where the resonator serves as a separate output filter stage for the inductor and capacitor based oscillator.

A temperature compensated oscillation controller includes a temperature compensation circuit configured to provide a reference voltage through a first terminal and to receive an input voltage including temperature information through a second terminal, and an oscillation circuit configured to be connected to an external crystal resonator through third and fourth terminals and to output a clock signal in response to an oscillation signal from the external crystal resonator. The temperature compensation circuit is configured to perform a voltage controlled oscillator-based sensing operation to convert the input voltage into a temperature code and to adjust a frequency of the clock signal using the temperature code.

An integrated circuit may include oscillator circuitry having a resonator formed from fin field-effect transistor (FinFET) devices. The resonator may include drive cells of alternating polarities and sense cells interposed between the drive cells. The resonator may be connected in a feedback loop within the oscillator circuitry. The oscillator circuitry may include an amplifier having an input coupled to the sense cells and an output coupled to the drive cells. The oscillator circuitry may also include a separate inductor and capacitor based oscillator, where the resonator serves as a separate output filter stage for the inductor and capacitor based oscillator.

An oscillation circuit includes an amplification circuit that causes a resonator to oscillate, and a variable capacitance circuit whose capacitance value is controlled on the basis of a control voltage. The variable capacitance circuit includes a first variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a first voltage, and a second variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a second voltage which is different from the first voltage. A capacitance value of the first variable capacitive element when the control voltage is the first voltage is different from a capacitance value of the second variable capacitive element when the control voltage is the second voltage.

An output buffer circuit includes an output node, a P-type transistor, an N-type transistor, and a first variable resistor circuit provided in a signal path between a drain of one of the P-type transistor and the N-type transistor and the output node.

A circuit device includes an A/D conversion unit, a processing unit that performs a temperature compensation process of an oscillation frequency based on temperature detection data and outputs frequency control data of the oscillation frequency, a D/A conversion unit, and an oscillation circuit. The D/A conversion unit (area DAC) is disposed on a first direction DR1 side of the A/D conversion unit (area ADC). When a direction crossing the first direction DR1 is defined as a second direction DR2, the processing unit (area DSPL) is disposed on the second direction DR2 side of the A/D conversion unit and the D/A conversion unit. When a direction opposite to the second direction DR2 is defined as a third direction DR3, the oscillation circuit (area OSC) is disposed on the third direction DR3 side or the first direction DR1 side of the D/A conversion unit.

A circuit device includes a control voltage input terminal to which a control voltage is inputted, an A/D conversion circuit A/D-converting the control voltage to generate control voltage data and A/D-converting a temperature detection voltage from a temperature sensor to generate temperature detection data, a processing circuit generating temperature compensation data of an oscillation frequency based on the temperature detection data and performing addition processing of the temperature compensation data and the control voltage data to generate frequency control data of the oscillation frequency, and an oscillation signal generation circuit generating an oscillation signal of the oscillation frequency set by the frequency control data, using the frequency control data and a resonator.

A circuit device includes a processing circuit and an oscillation signal generation circuit. The processing circuit performs Kalman filter processing for a result of phase comparison between an input signal based on an oscillation signal and a reference signal and performs loop filter processing for the result of phase comparison. The oscillation signal generation circuit generates the oscillation signal of an oscillation frequency set by frequency control data which is output data of the loop filter processing by using the frequency control data and a resonator. The processing circuit estimates a truth value for an observed value of the result of phase comparison by using the Kalman filter processing.

A circuit device includes an oscillation circuit, a clock signal output circuit that outputs a clock signal based on an output signal from the oscillation circuit, and an output control circuit. The output control circuit includes a counter circuit that performs a counting process on the basis of the output signal from the oscillation circuit, and a count enable signal generation circuit that outputs a count enable signal for the counter circuit. The counter circuit starts the counting process when the count enable signal becomes active, and outputs an output enable signal for the clock signal to the clock signal output circuit on the basis of a result of the counting process.

A circuit device includes an oscillation circuit configured to oscillate a resonator to thereby generate an oscillation signal, a waveform shaping circuit to which the oscillation signal is input, and which is configured to output a clock signal obtained by performing waveform shaping on the oscillation signal, a first duty adjustment circuit configured to perform a duty adjustment of the clock signal, and an output buffer circuit configured to output a first output clock signal and a second output clock signal to an outside based on the clock signal. The output buffer circuit includes a second duty adjustment circuit configured to perform a duty adjustment of the second output clock signal.