A bias circuit includes first to sixth transistors and first to fifth resistors. The collector of the fifth transistor is coupled to a node in a path connecting the collector of the fourth transistor and one end of the third resistor. The collector of the sixth transistor Tr6 is coupled to one end of the fifth resistor.

A monolithic semiconductor device includes: a substrate; a first nitride semiconductor layer disposed on the substrate; a second nitride semiconductor layer disposed on the first nitride semiconductor layer and having a band gap larger than a band gap of the first nitride semiconductor layer; a first transistor disposed on the substrate and including the first nitride semiconductor layer and the second nitride semiconductor layer, the first transistor being of a high-electron-mobility transistor (HEMT) type for power amplification; and a first bias circuit disposed on the substrate and including a second transistor of the HEMT type disposed outside a propagation path of a radio-frequency signal inputted to the first transistor, the first bias circuit applying bias voltage to a gate of the first transistor.

A power amplification device includes: a first semiconductor chip including a first main surface and a second main surface; a first field-effect transistor, a first drain finger part, a plurality of first gate finger parts, and a source finger part; a sub-mount substrate including a third main surface and a fourth main surface; and a first filled via provided penetrating from the third main surface to the fourth main surface. In plan view, the first filled via has a rectangular shape. A long side direction of the first filled via is parallel to a long side direction of the plurality of first gate finger parts. In plan view, the first filled via is positioned to overlap part of one first gate finger part included in the plurality of first gate finger parts.

A differential amplifier circuit includes: a control current source supplying a control current; paired bipolar transistors; an a variable resistance circuit including: a series circuit of a first resistor and a second resistor having an identical resistance, the series circuit electrically connected between a first terminal and a second terminal of the variable resistance circuit; a first field effect transistor (FET) having a source and a drain being electrically connected to emitters of the paired bipolar transistors, respectively; and a second FET having a drain, a gate being electrically connected to the drain thereof, the gate of the first FET, and a control terminal of variable resistance circuit, a source being electrically connected to a connection node between the first resistor and the second resistor, wherein the control current source adjusts the control current to allow transconductance of the second FET to be kept constant.

The present disclosure in some embodiments relates to a method of calibrating a power amplifier performance and an apparatus therefor, which provide an optimal calibration of the output characteristics of a power amplifier to all possible combinations in the input signal source by enabling individualized calibrations for changes in the output characteristics at room temperature and changing temperatures, thereby improving the performance of the power amplifier.

Provided is a temperature detection circuit that includes: a series connection circuit that is connected between a power supply voltage input terminal and ground and includes a temperature detection transistor and a first resistance element; and a current bypass circuit that includes a first transistor that is connected in parallel with the temperature detection element and allows a bypass current to flow therethrough. The temperature detection circuit outputs a temperature detection signal from a connection point between the temperature detection transistor and the first resistance element.

A bandgap reference circuit includes first through fourth bipolar junction transistors (BJTs). The base and collector of the first BJT are shorted together. The second BJT is coupled to the first BJT via a first resistor. The base of the third BJT is coupled to the base of the first BJT. The base and collector of the fourth BJT are coupled together and also are coupled to the base of the second BJT. A second resistor is coupled to the fourth emitter of the fourth BJT. A third resistor is coupled to the second resistor and to the emitter of the second BJT. An operational amplifier has a first input coupled to the first resistor and the collector of the second BJT, a second input coupled to the emitter of the third BJT and the collector of the fourth BJT, and an output coupled to the collectors of the first and third BJTs.

Aspects of this disclosure relate to a surface acoustic wave filter with an integrated temperature sensor. The integrated temperature sensor can be a resistive thermal device configured as a reflective grating for a surface acoustic wave resonator, for example. A radio frequency system can provide over temperature protection by reducing a power level of a radio frequency signal provided to the surface acoustic wave filter responsive to an indication of temperature provided by the integrated temperature sensor satisfying a threshold.

Radio frequency amplifier (200) assembly with effective prevention of RF interference. The radio frequency amplifier comprises an electrically conductive housing (301) that defines an enclosed interior of the radio frequency amplifier assembly, an electrically conductive cooling plate (415) disposed inside the electrically conductive housing and having a first side and an opposite second side, the electrically conductive cooling plate being configured to divide the enclosed interior into a first enclosed region (501) and a second enclosed region (503), and a radio frequency signal processing circuit board (223) equipped with a radio frequency signal processing circuit, the radio frequency signal processing circuit board being positioned in the first enclosed region and disposed on the first side of the electrically conductive cooling plate, and a power supply module and a controller module positioned in the second enclosed region and disposed on the opposite second side of the electrically conductive cooling plate.

Proposed are an antenna RF module and an antenna apparatus including the antenna RF modules. The antenna RF module includes an RF filter arranged on a front surface of a main board, a radiation element module arranged on a front surface of the RF filter, at least one reflector grill pin arranged between the RF filter and the radiation element module and grounding (GND) the radiation element module, outside air being introduced from in front of the RF filter to in back of the RF filter or being discharged from in back of the RF filter to in front of the RF filter through the at least one reflector grill pin, and a radome cover combined with the front surface of the RF filter and protecting the radiation element module from the outside. The antenna RF module provides the advantage of greatly improving overall performance in heat dissipation.