A compound semiconductor device comprises a heterojunction bipolar transistor including a plurality of unit transistors, a capacitor electrically connected between a RF input wire and a base wire for each unit transistor of the unit transistors, and a bump electrically connected to emitters of the unit transistors. The unit transistors are arranged in a first direction. The bump is disposed above the emitters of the unit transistors while extending in the first direction. The transistors include first and second unit transistors, the respective emitters of the first and second unit transistors being disposed on first and second sides, respectively, of a second direction, perpendicular to the first direction, with respect to a center line of the bump extending in the first direction. The capacitor is not covered by the bump, and respective lengths of the respective base wires connected respectively to the first and second unit transistors are different.

A radio frequency module includes: a first low-noise amplifier including a first amplification element as an input stage and a second amplification element as an output stage; a second low-noise amplifier including a third amplification element as an input stage and the second amplification element as an output stage, the third amplification element being different from the first amplification element; a first matching circuit connected to an input terminal of the first low-noise amplifier; and a module substrate including a first principal surface and a second principal surface opposite to each other, wherein the first amplification element is disposed on one of the first principal surface and the second principal surface, and the first matching circuit is disposed on the other of the first principal surface and the second principal surface.

A reconfigurable amplifier includes a first transistor having a gate coupled to an input of the reconfigurable amplifier, and a source coupled to a ground. The reconfigurable amplifier also includes a gate control circuit, and a second transistor having a gate coupled to the gate control circuit, a source coupled to a drain of the first transistor, and a drain coupled to an output of the reconfigurable amplifier, wherein the gate control circuit is configured to output a bias voltage to the gate of the second transistor in a cascode mode, and output a switch voltage to the gate of the second transistor in a non-cascode mode. The reconfigurable amplifier further includes a load coupled to the output of the reconfigurable amplifier.

An RF amplifier comprises a first ‘transconductance’ transistor (N.sub.CS) arranged to receive an RF input voltage (RFIN) at its gate terminal. A second ‘cascode’ transistor (N.sub.CG) has its source terminal connected to the drain terminal of the first transistor (N.sub.CS) at a node (MID). A feedback circuit portion is configured to measure a node voltage at the node (MID), to determine an average of the node voltage, to compare said average node voltage to a predetermined reference voltage (V.sub.BCG), and to generate a control voltage (CGGATE) dependent on the difference between the average node voltage and the predetermined reference voltage (V.sub.BCG). The feedback circuit portion applies the control voltage (CGGATE) to the gate terminal of the second transistor (N.sub.CG).

An RF amplifier comprises a first ‘transconductance’ transistor (N.sub.CS) arranged to receive an RF input voltage (RFIN) at its gate terminal. A second ‘cascode’ transistor (N.sub.CG) has its source terminal connected to the drain terminal of the first transistor (N.sub.CS) at a node (MID). A feedback circuit portion is configured to measure a node voltage at the node (MID), to determine an average of the node voltage, to compare said average node voltage to a predetermined reference voltage (V.sub.BCG), and to generate a control voltage (CGGATE) dependent on the difference between the average node voltage and the predetermined reference voltage (V.sub.BCG). The feedback circuit portion applies the control voltage (CGGATE) to the gate terminal of the second transistor (N.sub.CG).

The present disclosure provides a reconfigurable power amplifier (PA) based on a PIN switch and a design method thereof. The reconfigurable PA based on a PIN switch includes an input port, an input matching circuit, the PIN switch, a gate bias circuit, a transistor, a drain bias circuit, an output matching circuit and an output port, where the input matching network includes an input end connected to a power input end, and an output end connected to a gate of the transistor, the gate bias circuit is connected in parallel with the gate, the drain bias circuit is connected in parallel with a drain, the drain of the transistor is connected to an input end of the output matching circuit, and an output end of the output matching circuit serves as a power output.

The present disclosure provides a reconfigurable power amplifier (PA) based on a PIN switch and a design method thereof. The reconfigurable PA based on a PIN switch includes an input port, an input matching circuit, the PIN switch, a gate bias circuit, a transistor, a drain bias circuit, an output matching circuit and an output port, where the input matching network includes an input end connected to a power input end, and an output end connected to a gate of the transistor, the gate bias circuit is connected in parallel with the gate, the drain bias circuit is connected in parallel with a drain, the drain of the transistor is connected to an input end of the output matching circuit, and an output end of the output matching circuit serves as a power output.

A current flowing through a transistor of a final-stage amplifier is suppressed. A power amplification circuit includes a driving-stage amplifier, a final-stage amplifier, a power supply terminal, a first voltage control circuit, and a second voltage control circuit. The driving-stage amplifier includes a first transistor having a first input terminal, a first output terminal, and a first ground terminal. The final-stage amplifier includes a second transistor having a second input terminal, a second output terminal, and a second ground terminal. The first voltage control circuit is connected between the power supply terminal and the first output terminal, and controls a first power supply voltage applied to the first transistor. The second voltage control circuit is connected between the power supply terminal and the second output terminal, and controls a second power supply voltage applied to the second transistor.

A peak detector includes an asymmetrical latch having a first input and a second input; and a CMOS converter having a first input coupled to a first output of the asymmetrical latch, a second input coupled to a second output of the asymmetrical latch, and an output.

Various embodiments disclose a method and a device including: an antenna, a switching regulator, communication chip including an amplifier and a linear regulator operably connected to the amplifier and the switching regulator, the communication chip configured to transmit a radio-frequency signal from the electronic device through the antenna, and control circuitry configured to control the communication chip such that the linear regulator provides the amplifier with a voltage corresponding to an envelope of an input signal input to the amplifier, the input signal corresponding to the radio-frequency signal.