Abstract: An acoustic wave device includes a mounting substrate, and an acoustic wave element chip. The mounting substrate includes a first major surface with a bump-mounting electrode land thereon, and a second major surface facing the first major surface. The acoustic wave element chip includes a piezoelectric substrate including a major surface, and a functional electrode and a bump located over the major surface of the piezoelectric substrate. The bump is joined to the bump-mounting electrode land. A heat radiation pattern is located over the first major surface of the mounting substrate and located within a region facing the functional electrode of the acoustic wave element chip. The heat radiation pattern is connected to an internal layer portion of the mounting substrate between the first and second major surfaces, and not electrically connected to the bump-mounting electrode land on the first major surface.

Abstract: A filter device includes a filter between an input/output terminal and an input/output terminal, and an additional circuit connected in parallel with the filter. The filter includes at least two acoustic wave resonators defining a pass band of the filter. The additional circuit includes a longitudinally coupled resonator, and a capacitor connected between the longitudinally coupled resonator and the input/output terminal. A capacitance of a comb-shaped capacitance electrode of the capacitor is smaller than a capacitance of an IDT electrode of at least one acoustic wave resonator of the at least two acoustic wave resonators, and an area of the comb-shaped capacitance electrode of the capacitor is smaller than an area of the IDT electrode of the at least one acoustic wave resonator.

Abstract: An acoustic wave device includes a mounting substrate, and an acoustic wave element chip. The mounting substrate includes a first major surface with an electrode land thereon, and a second major surface facing the first major surface. The acoustic wave element chip includes a piezoelectric substrate including a major surface, and a functional electrode and a bump located over the major surface of the piezoelectric substrate. The bump is joined to the electrode land. A heat radiation pattern is located over the first major surface of the mounting substrate and located within a region facing the functional electrode of the acoustic wave element chip. The heat radiation pattern is connected to an internal layer portion of the mounting substrate between the first and second major surfaces, and not electrically connected to the electrode land on the first major surface.

Abstract: An elastic wave device includes an elastic wave element including a piezoelectric substrate with a first main surface and a second main surface that face each other, an IDT electrode disposed on the second main surface of the piezoelectric substrate, a support disposed on the second main surface of the piezoelectric substrate so as to surround the IDT electrode in plan view, and a cover that is disposed on the support and seals the IDT electrode together with the support and the piezoelectric substrate, a mounting substrate above which the elastic wave element is mounted, and a sealing resin that is disposed on the side of the side of the upper surface of the mounting substrate and seals the elastic wave element. A thickness of the mounting substrate is less than a thickness of the sealing resin that corresponds to a distance from a surface of the sealing resin in contact with the upper surface of the mounting substrate to a surface of the sealing resin on an opposite side of the mounting substrate.

Abstract: A filter device includes a filter between an input/output terminal and an input/output terminal, and an additional circuit connected in parallel with the filter. The filter includes at least two acoustic wave resonators defining a pass band of the filter. The additional circuit includes a longitudinally coupled resonator, and a capacitor connected between the longitudinally coupled resonator and the input/output terminal. A capacitance of a comb-shaped capacitance electrode of the capacitor is smaller than a capacitance of an IDT electrode of at least one acoustic wave resonator of the at least two acoustic wave resonators, and an area of the comb-shaped capacitance electrode of the capacitor is smaller than an area of the IDT electrode of the at least one acoustic wave resonator.

Abstract: A multiplexer includes a first filter that is a ladder elastic wave filter including series-arm resonators and parallel-arm resonators, a second filter connected to the first filter at a common connection point, and a board including an inductor pattern defining an inductor connected in parallel with the series-arm resonator, and a ground pattern provided in the layer in which the inductor pattern is provided, so as to be disposed at a distance from and adjacent to the inductor pattern. A minimum distance between the inductor pattern and the ground pattern is not greater than about 1.55 times a minimum pattern width in the ground pattern.

Abstract: A multiplexer includes a first filter that is a ladder elastic wave filter including series-arm resonators and parallel-arm resonators, a second filter connected to the first filter at a common connection point, and a board including an inductor pattern defining an inductor connected in parallel with the series-arm resonator, and a ground pattern provided in the layer in which the inductor pattern is provided, so as to be disposed at a distance from and adjacent to the inductor pattern. A minimum distance between the inductor pattern and the ground pattern is not greater than about 1.55 times a minimum pattern width in the ground pattern.

Abstract: A filter device includes a filter chip on a multilayer substrate. The filter chip includes a reception filter chip portion and a transmission filter chip portion, and a reception filter defined by a first bandpass filter includes first and second balanced output terminals. First and second balance wirings connect first and second balanced input pads and first and second balanced output pads provided on a second principal surface of the multilayer substrate. The first and second balance wirings cross each other within the multilayer substrate and are electrically insulated from each other. A portion of a ground conductor is disposed at a region in which the first and second balance wirings overlap, interposed between portions of the first and second balance wirings, and disposed at a different substrate layer.

Abstract: A filter device includes a filter chip on a multilayer substrate. The filter chip includes a reception filter chip portion and a transmission filter chip portion, and a reception filter defined by a first bandpass filter includes first and second balanced output terminals. First and second balance wirings connect first and second balanced input pads and first and second balanced output pads provided on a second principal surface of the multilayer substrate. The first and second balance wirings cross each other within the multilayer substrate and are electrically insulated from each other. A portion of a ground conductor is disposed at a region in which the first and second balance wirings overlap, interposed between portions of the first and second balance wirings, and disposed at a different substrate layer.

Abstract: An elastic wave device includes an elastic wave element including a piezoelectric substrate with a first main surface and a second main surface that face each other, an IDT electrode disposed on the second main surface of the piezoelectric substrate, a support disposed on the second main surface of the piezoelectric substrate so as to surround the IDT electrode in plan view, and a cover that is disposed on the support and seals the IDT electrode together with the support and the piezoelectric substrate, a mounting substrate above which the elastic wave element is mounted, and a sealing resin that is disposed on the side of the side of the upper surface of the mounting substrate and seals the elastic wave element. A thickness of the mounting substrate is less than a thickness of the sealing resin that corresponds to a distance from a surface of the sealing resin in contact with the upper surface of the mounting substrate to a surface of the sealing resin on an opposite side of the mounting substrate.