Abstract: A first transmission line transformer receives and outputs an unbalanced signal and performs impedance transformation. A second transmission line transformer performs unbalanced-to-balanced transformation. The first transmission line transformer includes a first main line and a first sub-line. The direction of the first main line is identical to the direction of the first sub-line. An end of the first sub-line is grounded. An end of the first main line is coupled to the unbalanced-signal input/output node. The second transmission line transformer includes a second main line and a second sub-line. The direction of the second main line is identical to a direction of the second sub-line. An end of the second main line and the second sub-line are grounded. An end of the second main line and the second sub-line are coupled to the balanced-signal input/output nodes.

Abstract: An amplifier device includes an amplifier including cascade-connected power amplifiers in a plurality of stages and a bias circuit configured to supply bias currents to the amplifier. A bias current supplied to a power amplifier in the first stage of the power amplifiers in the plurality of stages exhibits a positive temperature characteristic. A bias current supplied to a power amplifier in the final stage exhibits a negative temperature characteristic.

Abstract: A temperature detection circuit includes a first temperature sensor unit that includes a temperature sensor configured to detect a temperature of a target object and that is configured to output a first analog signal indicating the detected temperature, a second temperature sensor unit that includes a temperature sensor configured to detect a temperature of the target object and that is configured to output a second analog signal indicating the detected temperature, and an AD converter configured to convert the second analog signal into a digital signal and configured to output the digital signal.

Abstract: An amplifier includes a transistor on a side to which a radio-frequency signal is input and a transistor on a side to which the radio-frequency signal is output that are connected in cascade. The amplifier includes an input matching network connected to an input end of the transistor, and an output matching network connected to an output end of the transistor. The input matching network includes a transmission line transformer. The transmission line transformer includes lines. One of the lines is connected between an input terminal for the radio-frequency signal and the transistor. The other line is disposed so as to be able to couple to the line via an electromagnetic field, one end thereof is connected to a node between the line and the input terminal for the radio-frequency signal, and another end thereof is connected between the line and a ground potential.

Abstract: A high-frequency circuit includes an amplifier, a power distributor disposed on an output route of the amplifier, a first by-pass route that bypasses the amplifier, a second by-pass route that bypasses the power distributor, a first switch and a second switch disposed in series on the first by-pass route, and a third switch disposed in series on the second by-pass route. The first by-pass route is connected to a first node on a route connecting a signal input terminal and the amplifier and a second node on a route connecting the amplifier and the power distributor. The second by-pass route is connected to a third node between the first switch and the second switch and a fourth node on an output route of the power distributor.

Abstract: Provided is an amplification circuit that includes: a low-noise amplifier that includes an FET as an amplification element and that amplifies a radio-frequency signal inputted to the gate of the FET; an input matching network that matches the input impedance of the low-noise amplifier; and a switch that is serially connected between ground and a node on a line connecting the input matching network and the gate of the FET to each other.

Abstract: A radio-frequency circuit includes: an amplifier; a matching circuit connected to an output side of the amplifier; and a power splitter connected to an output side of the matching circuit. The power splitter includes a differential inductor and a resistor element. The differential inductor includes an input node (ni), a first line, and a second line. The input node (ni) is connected to the matching circuit. The first line and the second line are respectively wound into coil form and connected to the input node (ni). The resistor element forms a connection between a node (n1) on an output side of the first line and a node (n2) on an output side of the second line. The first line and the second line are wound in opposite directions and have the same coil axis.

Abstract: An amplifier circuit amplifies a radio-frequency signal. The amplifier circuit includes an amplifier, an input matching circuit connected to an input side of the amplifier and matches impedance, and a protection circuit connected to a node in a path within a path between an input matching circuit and the amplifier. The protection circuit includes a first diode connected between the node and a ground, and a second diode connected in parallel with the first diode and connected in a direction opposite to the first diode between the node and the ground. A threshold voltage of each of the first diode and the second diode is greater than a maximum voltage amplitude of the input signal at the node and is less than a difference between a withstand voltage of the amplifier and the bias voltage.

Abstract: An amplification circuit includes: an amplifier including a transistor that is connected between an input terminal and an output terminal; an input matching network that is connected between the input terminal and an input side of the amplifier and converts an impedance from a low impedance to a high impedance; a limiter circuit that is connected between a node between the input matching network and the input side of the amplifier, and ground and includes two diodes connected in opposite directions to each other; and a capacitor that is connected in series with the limiter circuit between the node and ground.

Abstract: An amplifier device includes an amplifier including cascade-connected power amplifiers in a plurality of stages and a bias circuit configured to supply bias currents to the amplifier. A bias current supplied to a power amplifier in the first stage of the power amplifiers in the plurality of stages exhibits a positive temperature characteristic. A bias current supplied to a power amplifier in the final stage exhibits a negative temperature characteristic.

Abstract: A high-frequency circuit includes an amplifier, a power distributor disposed on an output route of the amplifier, a first by-pass route that bypasses the amplifier, a second by-pass route that bypasses the power distributor, a first switch and a second switch disposed in series on the first by-pass route, and a third switch disposed in series on the second by-pass route. The first by-pass route is connected to a first node on a route connecting a signal input terminal and the amplifier and a second node on a route connecting the amplifier and the power distributor. The second by-pass route is connected to a third node between the first switch and the second switch and a fourth node on an output route of the power distributor.

Abstract: Provided is an amplification circuit that includes: a low-noise amplifier that includes an FET as an amplification element and that amplifies a radio-frequency signal inputted to the gate of the FET; an input matching network that matches the input impedance of the low-noise amplifier; and a switch that is serially connected between ground and a node on a line connecting the input matching network and the gate of the FET to each other.

Abstract: An amplifier circuit amplifies a radio-frequency signal. The amplifier circuit includes an amplifier, an input matching circuit connected to an input side of the amplifier and matches impedance, and a protection circuit connected to a node in a path within a path between an input matching circuit and the amplifier. The protection circuit includes a first diode connected between the node and a ground, and a second diode connected in parallel with the first diode and connected in a direction opposite to the first diode between the node and the ground. A threshold voltage of each of the first diode and the second diode is greater than a maximum voltage amplitude of the input signal at the node and is less than a difference between a withstand voltage of the amplifier and the bias voltage.

Abstract: A voltage supply circuit includes a level shifter that switches between voltages of two voltage input units and that outputs one of the voltages, a charge pump that transforms a voltage of an input power supply and that applies the transformed voltage to the level shifter, and a charge pump control circuit. The voltage supply circuit controls supply and interruption of a predetermined voltage to a voltage-supplied circuit (RF switch 20). The charge pump control circuit causes the charge pump to perform a continuous operation in an on-mode and to perform an intermittent operation in an off-mode, the off-mode representing a state in which the voltage supply to the voltage-supplied circuit (RF switch 20) is stopped, the on-mode representing a state in which the predetermined voltage is supplied.

Abstract: A radio-frequency circuit includes: an amplifier; a matching circuit connected to an output side of the amplifier; and a power splitter connected to an output side of the matching circuit. The power splitter includes a differential inductor and a resistor element. The differential inductor includes an input node (ni), a first line, and a second line. The input node (ni) is connected to the matching circuit. The first line and the second line are respectively wound into coil form and connected to the input node (ni). The resistor element forms a connection between a node (n1) on an output side of the first line and a node (n2) on an output side of the second line. The first line and the second line are wound in opposite directions and have the same coil axis.

Abstract: A temperature detection circuit includes a first temperature sensor unit that includes a temperature sensor configured to detect a temperature of a target object and that is configured to output a first analog signal indicating the detected temperature, a second temperature sensor unit that includes a temperature sensor configured to detect a temperature of the target object and that is configured to output a second analog signal indicating the detected temperature, and an AD converter configured to convert the second analog signal into a digital signal and configured to output the digital signal.

Abstract: An amplification circuit includes: an amplifier including a transistor that is connected between an input terminal and an output terminal; an input matching network that is connected between the input terminal and an input side of the amplifier and converts an impedance from a low impedance to a high impedance; a limiter circuit that is connected between a node between the input matching network and the input side of the amplifier, and ground and includes two diodes connected in opposite directions to each other; and a capacitor that is connected in series with the limiter circuit between the node and ground.

Abstract: A voltage supply circuit includes a level shifter that switches between voltages of two voltage input units and that outputs one of the voltages, a charge pump that transforms a voltage of an input power supply and that applies the transformed voltage to the level shifter, and a charge pump control circuit. The voltage supply circuit controls supply and interruption of a predetermined voltage to a voltage-supplied circuit (RF switch 20). The charge pump control circuit causes the charge pump to perform a continuous operation in an on-mode and to perform an intermittent operation in an off-mode, the off-mode representing a state in which the voltage supply to the voltage-supplied circuit (RF switch 20) is stopped, the on-mode representing a state in which the predetermined voltage is supplied.

Abstract: A level conversion circuit (10) includes an EFET (11), a diode (12) and resistors (13, 14). The drain of the EFET (11) is connected to an output terminal of the level conversion circuit (10). The drain and the gate of the EFET (11) are in conductive contact with each other. The source of the EFET (11) is grounded via the resistor (13). The drain of the EFET (11) is connected to one end of the resistor (14). The other end of the resistor (14) is connected to the cathode of the diode (12). The anode of the diode (12) is connected to a control voltage input terminal.

Abstract: A semiconductor package includes the following elements. A high-output switch IC includes an IC top surface on which an electrode is disposed and an IC bottom surface on which no electrode is disposed. A connecting terminal is formed at a position outside a projection region toward a side portion of the semiconductor package. The projection region is a region projected in a thickness direction of the high-output switch IC. A wire electrically connects the electrode and the connecting terminal. A mold resin section covers the IC top surface and the wire and also covers a surface of the connecting terminal to which the wire is connected. A surface of the connecting terminal opposite to the surface to which the wire is connected is not covered with the mold resin section but is exposed. The IC bottom surface is not covered with a metal.