Abstract: A radio-frequency module includes a first base made of a first semiconductor material; a second base that is made of a second semiconductor material having a thermal conductivity lower than that of the first semiconductor material and which includes a power amplifier circuit; a third base including a transmission filter circuit; and a module substrate having a main surface on which the first base, the second base, and the third base are arranged. The first base is joined to the main surface via an electrode. The second base is arranged between the module substrate and the first base in a sectional view and is joined to the main surface via an electrode. At least part of the first base is overlapped with at least part of the second base and at least part of the third base in a plan view.

Abstract: A power amplifier circuit includes a differential amplifier circuit configured to amplify a radio-frequency signal, a transformer disposed on an output side with respect to the differential amplifier circuit and including a primary winding and a secondary winding, and a dispersion circuit coupled to a midpoint of the primary winding of the transformer and configured to operate as an adjustment circuit. The dispersion circuit is configured to adjust, based on a supply voltage controlled in accordance with the envelope of the radio-frequency signal, a bias (bias current or bias voltage) to be supplied to the differential amplifier circuit.

Abstract: A clamping circuit is connected between a ground potential and a node through which a radio frequency signal passes. The clamping circuit includes multiple clamping elements that are cascaded. Each of the multiple clamping elements becomes conductive when a voltage greater than or equal to a forward voltage is applied thereto. At least one of the multiple clamping elements is implemented by a resistor-connected transistor that includes a bipolar transistor and a base-collector resistance element connected between the base and the collector of the bipolar transistor.

Abstract: In a semiconductor device, a first member having a first surface includes a plurality of circuit blocks disposed in an inner region of the first surface when the first surface is viewed in plan. The second member is joined to the first surface of the first member in surface contact with the first surface. The second member includes a plurality of first transistors that are connected in parallel to each other and form a first amplifier circuit. A conductive protrusion protrudes from the second member on an opposite side to the first member. The first transistors are disposed in a region not overlapping any of the circuit blocks in the first member in a plan view.

Abstract: A power amplifier circuit according to the present disclosure includes an amplifier circuit serving as a differential amplifier circuit configured to be activated by a supply voltage that is variable in accordance with amplitude of a signal, a bias circuit configured to output a bias to be supplied to the amplifier circuit, and first and second dispersion circuits respectively provided for a pair of differential signals outputted from the amplifier circuit and configured to control dependence of gain of the differential amplifier circuit on the supply voltage.

Abstract: A power amplifying circuit includes a single-ended amplifier, a differential amplifier, a first balun transformer, a second balun transformer, and a first switching circuit. The single-ended amplifier operates in a first mode and a second mode different from the first mode. The differential amplifier operates in the second mode. The first balun transformer converts an unbalanced output signal from the single-ended amplifier into a differential signal and outputs the differential signal to the differential amplifier. The second balun transformer converts a balanced output signal from the differential amplifier into an unbalanced output signal. The first switching circuit outputs the unbalanced output signal from the single-ended amplifier in the first mode and outputs the unbalanced output signal from the second balun transformer in the second mode.

Abstract: In a semiconductor device, when a first surface of a first member is viewed in plan, a plurality of circuit blocks are disposed in an inner region of the first surface. The second member is joined to the first surface of the first member in surface contact with the first surface. The second member includes one or more circuit blocks. A conductive protrusion protrudes from the second member on an opposite side to the first member. One of the circuit blocks in the second member constitutes a first amplifier circuit including a plurality of first transistors that are connected in parallel to each other. At least one of the circuit blocks in the first member overlaps at least one circuit block in the second member in a plan view.

Abstract: A second member is joined in surface contact with a first surface of a first member including a semiconductor region made from an elemental semiconductor. The second member includes a radio-frequency amplifier circuit made from a compound semiconductor. A conductive protrusion projects from the second member toward a side opposite to the first member. The first member includes a temperature measurement element that detects a temperature.

Abstract: A power amplifier circuit includes a first amplifier circuit configured to amplify a first signal of a first frequency band and output a first amplified signal having a first power, a second amplifier circuit configured to amplify a second signal of the first frequency band or a second frequency band different from the first frequency band and output a second amplified signal having a second power different from the first power, and a first variable adjustment circuit disposed between the second amplifier circuit and a first circuit subsequent to the second amplifier circuit, the first variable adjustment circuit being configured to be capable of adjusting a first impedance of the first circuit seen from the second amplifier circuit.

Abstract: A composite board includes a first member and a second member on a first surface that is one surface of the first member. A first conductor protrusion protrudes from the second member in a direction in which the first surface faces. A second conductor protrusion protrudes from the composite board in the direction in which the first surface faces. The first member includes a first semiconductor board, and the second member includes a second semiconductor board having lower thermal conductivity than the first semiconductor board. A radio frequency amplifier circuit including first transistors is in the second member. The first conductor protrusion is electrically connected to the first transistors and at least partially overlaps with the first transistors in a plan view of the first surface. The composite board includes a connection part that reaches the first semiconductor board or the second semiconductor board from the second conductor protrusion.

Abstract: A mesa structure including a collector layer, a base layer, and an emitter layer laminated on a substrate is formed. An emitter electrode electrically connected to the emitter layer is disposed on the mesa structure. Moreover, a base electrode electrically connected to the base layer is disposed on the mesa structure. A collector electrode is disposed in such a manner as to surround the mesa structure in plan view, and the collector electrode is electrically connected to the collector layer. The emitter electrode includes a first part and a second part. In plan view, the base electrode surrounds the first part of the emitter electrode, and the second part of the emitter electrode surrounds the base electrode.

Abstract: A first differential amplifier circuit is in or on a substrate and includes a pair of differential input nodes to which differential signals are input and a pair of differential output nodes from which differential signals are output. Ends of a secondary coil of a first transformer are connected to the pair of differential input nodes of the first differential amplifier circuit, and an intermediate point of the secondary coil is AC grounded. Ends of a primary coil of a second transformer are connected to the pair of differential output nodes of the first differential amplifier circuit, and an intermediate point of the primary coil of the second transformer is AC grounded. A differential wire pair connects the ends of the secondary coil of the first transformer to the pair of differential input nodes of the first differential amplifier circuit.

Abstract: The present invention relates to a viscosity index improver containing a copolymer (A) that contains, as essential constituent monomers, a fluorine atom-containing monomer (a) represented by the following formula (1) and a monomer (b) represented by the following formula (2), wherein the copolymer (A) has a solubility parameter of 8.1 to 10.0 (cal/cm3)1/2, and a mass ratio (b/a) of the monomer (b) to the monomer (a) in the monomers constituting the copolymer (A) is 0.

Abstract: In a semiconductor device, when a first surface of a first member is viewed in plan, at least one switch circuit including a switch is disposed within the first surface. A second member is joined to the first surface of the first member in surface contact with the first surface. The second member includes a plurality of transistors that are made of a compound semiconductor and form a radio-frequency amplifier circuit. A first conductive protrusion protrudes from the second member on an opposite side to the first member. The first member includes a circuit element disposed between the radio-frequency amplifier circuit and the at least one switch circuit in a plan view, the circuit element not forming the switch circuit.

Abstract: A semiconductor devices comprises a first member including a first circuit partially formed by an elemental semiconductor element at a surface layer, a first conductive raised portion at the first member, and a second member smaller than the first member in plan view joined to the first member. The second member includes a second circuit partially formed by a compound semiconductor element. A second conductive raised portion is at the second member. A power amplifier includes a first-stage amplifier circuit included in the first or second circuit and a second-stage amplifier circuit included in the second circuit. The first circuit includes a first switch for inputting to the first-stage amplifier circuit a radio-frequency signal inputted to a selected contact, a control circuit to control the first- and second-stage amplifier circuits, and a second switch for outputting from a selected contact a radio-frequency signal outputted by the second-stage amplifier circuit.

Abstract: In a flow path switching valve, when a valve rod is shifted toward a first back pressure chamber, a first valve chamber is separated from the first back pressure chamber by a first valve element, and a second valve chamber is separated from an intermediate chamber by a second valve element. When the valve rod is shifted toward a second back pressure chamber, the first valve chamber is separated from the intermediate chamber by the first valve element, and the second valve chamber is separated from the second back pressure chamber by the second valve element. The valve rod has a pressure equalizing path through which the first back pressure chamber and the second back pressure chamber are connected.

Abstract: A semiconductor module comprises a first member including a semiconductor substrate made of a compound semiconductor and a first electronic circuit on the semiconductor substrate is mounted on a mounting surface of a module substrate, and a second member including a semiconductor layer formed of a single semiconductor thinner than the semiconductor substrate of the first member and a second electronic circuit on the semiconductor layer is bonded to an upper surface of the first member. First and second pads are respectively connected to the first electronic circuit on the first member and the second electronic circuit on the second member. A first wire connects the first pad and a substrate side pad. A second wire connects the second pad and a substrate side pad. An inter-member connection wire made of a conductor film on the first and second members connects the first and second electronic circuits.

Abstract: A stacked semiconductor device capable of increasing heat dissipation comprises a first member and a second member. The first member includes a semiconductor substrate and a first electronic circuit. The first electronic circuit includes a semiconductor element provided on one surface of the semiconductor substrate. A second member is attached to a first surface, which is one surface of the first member. The second member includes a second electronic circuit including another semiconductor element. The second member is provided with a first opening that penetrates the second member in a thickness direction. A first conductor projection is coupled to the first electronic circuit. The first conductor projection protrudes from the first surface of the first member through the first opening of the second member to the outside of the first opening.

Abstract: A power amplifier circuit includes a first transistor having a first terminal to which a first signal inputs, a second transistor having a first terminal to which the first signal inputs, a first resistor having a first end to which a first bias current is supplied and a second end electrically connected to the first terminal of the first transistor, a second resistor having a first end to which a second bias current is supplied and a second end electrically connected to the first terminal of the second transistor, and a third resistor having a first end connected to the first end of the first resistor and a second end connected to the first end of the second resistor.

Abstract: In a semiconductor device, plural cells are disposed side by side on a substrate in a first direction. Each of the plural cells includes a bipolar transistor, an emitter electrode contained in a base layer of the bipolar transistor as viewed from above, and a base electrode. The bipolar transistors of the plural cells are connected in parallel with each other. Among the plural cells, the breakdown resistance of at least one second cell, which is other than a first cell disposed at each end, is higher than that of the first cell. It is possible to provide a semiconductor device that can reduce the deterioration of the breakdown resistance when flip-chip mounting is employed, as well as when face-up mounting is employed.