Disclosed is a temperature-compensated crystal oscillator based on analog circuit; a closed-loop compensation architecture determines the temperature compensation of a crystal oscillator. The power splitter divides the VCXO's current output signal with frequency f=f.sub.0+Δf into two signals, one signal to output of the TCXO and the other signal is sent to an analog frequency-voltage conversion circuit. According to the frequency of the VCXO's current output signal, the analog frequency-voltage conversion circuit produces a voltage signal V(T), which corresponds to current ambient temperature. The difference between V(T) and a reference voltage signal V.sub.ref is produced and amplified to obtain a compensation voltage signal ΔV through a voltage matching circuit. ΔV is smoothed by a filter, then sent to the voltage control terminal of the VCXO to make the VCXO generate a stable signal with desired frequency f.sub.0, to compensate the frequency of the VCXO's output signal when the ambient temperature is changed.

A quartz crystal unit comprising a quartz crystal resonator having a base portion, and first and second tuning fork arms connected to the base portion, the base portion having a length less than 0.5 mm and greater than a spaced-apart distance between the first and second tuning fork arms, each of the first and second tuning fork arms having a width less than 0.1 mm and a length less than 1.56 mm, and a plurality of different widths including a first width and a second width greater than the first width, at least one groove being formed in at least one of opposite main surfaces of each of the first and second tuning fork arms so that a length of the at least one groove is within a range of 0.3 mm to 0.79 mm, the quartz crystal resonator being housed in a case, and a lid being connected to the case.

The digital-output temperature sensor includes a temperature sensor circuit, a current mirror circuit which makes a mirror current of a temperature detection current flow and pulls in a mirror current of a reference current to thereby output a first difference current from a first output node and output a second difference current from a second output node, a chopping circuit, and an A/D conversion circuit. The chopping circuit performs a chopping operation of making the mirror current of the reference current flow in a second state through a transistor of the current mirror circuit through which the mirror current of the temperature detection current flows in a first state, and making the mirror current of the temperature detection current flow in the second state through the transistor of the current mirror circuit through which the mirror current of the reference current flows in the first state.

The present disclosure relates to an electronic device comprising a first capacitor and a quartz crystal coupled in series between a first node and a second node; an inverter coupled between the first and second nodes; a first variable capacitor coupled between the first node and a third node; and a second variable capacitor coupled between the second node and the third node.

Provided is a temperature sensor including a bipolar transistor, a resistor, and a variable resistance circuit. The resistor is provided between a first node coupled to a base node of the bipolar transistor and a collector node of the bipolar transistor. The variable resistance circuit is provided between an emitter node of the bipolar transistor and a ground node.

A variable capacitance circuit includes a capacitor array having a first capacitor in which a plurality of MIM capacitors are coupled in parallel and a second capacitor in which a plurality of MIM capacitors are coupled in series, and a switch array having a first switch and a second switch. A shape pattern of at least one of a first electrode of the first capacitor, a first ground shield, a second electrode of the second capacitor, and a second ground shield is set so that a first capacitance difference per 1 LSB between first capacitance values of the first capacitor when the first switch is turned on and off and a second capacitance difference per 1 LSB between second capacitance values of the second capacitor when the second switch is turned on and off are close to each other.

A vibration device includes a semiconductor substrate having a first surface and a second surface in an obverse-reverse relationship, a vibration element disposed on the first surface, a lid bonded to the first surface, an integrated circuit disposed on the first surface, a terminal disposed on the second surface, a through electrode which penetrates the semiconductor substrate, and is configured to electrically couple the terminal and the integrated circuit to each other, and a first capacitor which is provided with a first recess provided to the semiconductor substrate and opening in the first surface, an insulating film disposed on an inside surface of the first recess, and an electrically-conductive material filling the first recess, and has a first capacitance between the electrically-conductive material and the semiconductor substrate, wherein the electrically-conductive material does not have contact with the terminal at the second surface side.

A circuit device includes an oscillation circuit configured to generate an oscillation signal, a first pre-driver disposed in a posterior stage of the oscillation circuit, a first output driver disposed in a posterior stage of the first pre-driver, a first regulator configured to supply a first regulated voltage to the first pre-driver, and a second regulator configured to supply a second regulated voltage to the first output driver, wherein the second regulator is shorter in transient response time than the first regulator.

A circuit device includes an oscillation circuit that generates an oscillation signal using a resonator, a temperature detection circuit that outputs temperature detection data, a temperature compensation circuit, and a temperature detection rate control circuit. The temperature compensation circuit performs temperature compensation on an oscillation frequency of the oscillation signal based on the temperature detection data. The temperature detection rate control circuit controls a temperature detection rate at which the temperature detection circuit executes temperature detection. At this time, the temperature detection rate control circuit controls the temperature detection rate based on a variation in the temperature detection data.

A circuit device includes an oscillation circuit generating an oscillation signal by oscillating a vibrator, a temperature sensor circuit performing an intermittent operation, a logic circuit performing temperature compensation processing based on an output of the temperature sensor circuit, and a power supply circuit supplying power to the oscillation circuit. The oscillation circuit is disposed in a circuit region, the temperature sensor circuit and the logic circuit are disposed in a circuit region, and the power supply circuit is disposed in a circuit region, which is positioned between the circuit region and the circuit region.