A quartz crystal resonator includes a quartz crystal resonator element, a thermistor, and a package base having a first principal surface and a second principal surface having an opposed surface relationship with each other, the quartz crystal resonator element is mounted on the first principal surface side, the thermistor is housed in a recessed section of the second principal surface side of the package base, a plurality of electrode terminals connected to the quartz crystal resonator element or the thermistor is disposed on the second principal surface side of the package base, and a distance in a first direction perpendicular to the first principal surface from a mounting surface of the electrode terminals to the thermistor is equal to or longer than 0.05 mm.

A radio-frequency module includes a mount board, an electronic component, an external connection terminal, and an acoustic wave filter. The mount board has a first principal surface and a second principal surface facing each other. The electronic component is arranged on the first principal surface of the mount board. The external connection terminal is arranged on the second principal surface of the mount board. The acoustic wave filter is arranged on the second principal surface of the mount board. The acoustic wave filter is a bare-chip acoustic wave filter. The radio-frequency module is suppressed in height along a thickness of the mount board.

A quartz crystal resonator includes a quartz crystal resonator element, a thermistor, and a package base having a first principal surface and a second principal surface having an opposed surface relationship with each other, the quartz crystal resonator element is mounted on the first principal surface side, the thermistor is housed in a recessed section of the second principal surface side of the package base, a plurality of electrode terminals connected to the quartz crystal resonator element or the thermistor is disposed on the second principal surface side of the package base, and a distance in a first direction perpendicular to the first principal surface from a mounting surface of the electrode terminals to the thermistor is equal to or longer than 0.05 mm.

A structure of an integrated crystal oscillator package has a first quartz crystal resonator, a second quartz crystal resonator, and application-specific integrated circuit chip (ASIC) combined in a package. The ASIC has a switch control for receiving audio formats of 44.1 kHz and 48 kHz with different hi-fidelity (hi-fi). The first quartz crystal resonator has a first clock rate corresponding to the 44.1 kHz frequency and the second quartz crystal resonator has a second clock rate corresponding to the 48 kHz frequency to be switched by the present invention in operation.

A crystal oscillator internally includes a package storing a crystal unit. The crystal oscillator is configured to include: a substrate having one surface side on which the crystal unit is disposed and another surface side on which a circuit component and a heating element are disposed, the circuit component including an oscillator circuit that oscillates the crystal unit, and the heating element regulating a temperature inside the package; a stepped portion formed at an inner wall of the package to support only an end portion of the substrate from the one surface side such that the crystal unit, the circuit component, and the heating element are spaced from a wall portion of the package; and a wire that connects between a terminal disposed at the heating element and a terminal disposed inside the package without via the substrate.

A radio-frequency module is provided that includes a structure, a filtering element disposed on the structure, a switching element embedded in the structure, and an impedance element connected to the switching element and the filtering element. In a plan view of the structure, the switching element and the filtering element overlap each other in at least part thereof. The structure has a plurality of vias including a via , a via and a via. The via connects the input-output terminal and the filtering element. The via connects the ground terminal and an impedance adjustment circuit including the switching element and the impedance element. In a plan view, the via is located in a smallest rectangular region encompassing the vias.

An acoustic wave device includes: a support substrate; a first piezoelectric substrate bonded to a first principal surface of the support substrate, the first piezoelectric substrate being a single crystal substrate, a first acoustic wave resonator located on an opposite surface of the first piezoelectric substrate from a surface to which the support substrate is bonded, the first acoustic wave resonator including an IDT; a second piezoelectric substrate bonded to a second principal surface of the support substrate opposite from the first principal surface, the second piezoelectric substrate being a single crystal substrate; and a second acoustic wave resonator located on an opposite surface of the second piezoelectric substrate from a surface to which the support substrate is bonded, the second acoustic wave resonator including an IDT.

A vibrating element includes a piezoelectric substrate having an excitation section adapted to excite a thickness-shear vibration, and provided with a step section in each of side surfaces on both ends, and a peripheral section having a thickness smaller than a thickness of the excitation section, and the peripheral section has at least one projection section disposed on both principal surfaces in an area where a vibratory displacement when the excitation section excites a vibration is sufficiently attenuated.

An electronic device includes a first conductive pattern and a second conductive pattern that are disposed on a main surface of an insulating substrate, a first electrode pattern that is electrically connected to the first conductive pattern, and a vibrator element that is disposed on the main surface, and the area of a first section in which the first conductive pattern overlaps the first electrode pattern is greater than the area in which the other conductive pattern overlaps the first electrode pattern in a plan view.

A piezoelectric vibrator according to the invention has a base, an integrated circuit element, and a piezoelectric vibration element. The base has internal terminal pads, and external terminals including an AC output terminal. The base includes rectangular ceramic substrate layers stacked in at least three layers, each of which has castellations formed at four corners. Among the internal terminal pads, internal terminal pads for the integrated circuit element and internal terminal pads for the piezoelectric vibration element are connected to each other by externally exposed wiring patterns formed on upper surfaces of the castellations at the corners of the ceramic substrate constituting a middle layer.