A multiple-stage amplifier includes a driver stage die and a final stage die. The driver stage die includes a first type of semiconductor substrate (e.g., a silicon substrate), a first transistor, and an integrated portion of an interstage impedance matching circuit. A control terminal of the first transistor is electrically coupled to an RF signal input terminal of the driver stage die, and the integrated portion of the interstage impedance matching circuit is electrically coupled between a current-carrying terminal of the first transistor and an RF signal output terminal of the driver stage die. The second die includes a III-V semiconductor substrate (e.g., a GaN substrate) and a second transistor. A connection, which is a non-integrated portion of the interstage impedance matching circuit, is electrically coupled between the RF signal output terminal of the driver stage die and an RF signal input terminal of the final stage die.

An embodiment of a Doherty amplifier module includes a substrate, a first amplifier die, and a second amplifier die. The first amplifier die includes one or more first power transistors configured to amplify, along a first signal path, a first input RF signal to produce an amplified first RF signal. The second amplifier die includes one or more second power transistors configured to amplify, along a second signal path, a second input RF signal to produce an amplified second RF signal. The first and second amplifier die each also include an elongated output pad that is configured to enable a pluralities of wirebonds to be connected in parallel along the length of the elongated output pad so that the pluralities of wirebonds extend in perpendicular directions to the first and second signal paths.

A power splitter that amplifies an input radio-frequency (RF) signal. The power splitter uses a single transistor in a common emitter stage of a cascode amplifier and two or more common base stages of the cascode amplifier to amplify and to split the input RF signal. A common base biasing signal can be used to simultaneously enable two or more of the common base stages to generate two or more amplified RF output signals.

A gate bias circuit for a plurality of GaAs amplifier stages is a transistor coupled to a temperature compensation current received from a CMOS control stage. A plurality of pHEMPT amplifier stages are coupled to the gate bias circuit and to a control voltage which switches the amplifier stage. A selectively controlled stage pass transistor enables a current mirror between the gate bias circuit and each stage amplifying transistor. The penultimate pHEMPT amplifier stage is coupled to a CMOS amplifier. A CMOS circuit provides both the temperature compensation current by a proportional to absolute temperature (PTAT) circuit and the control voltage enabling each pHEMPT transistor to receive its input signal in combination with the gate bias voltage.

A power amplifying device includes first unit transistors and second unit transistors. The first unit transistors are connected in parallel and configured to amplify a radio frequency signal and to output a resultant signal. The second unit transistors are connected in parallel and configured to amplify the signal output by the first unit transistors and to output a resultant signal. Each of the first unit transistors is smaller than each of the second unit transistors.

An embodiment provides an amplifier system with multiple amplification paths connected to a combiner for combination of signals amplified in the amplification paths, each amplification path comprising an amplifier and a matching network provided between the amplifier and the combiner, wherein the individual amplifiers can interact through the combiner, causing an active load-pull effect. The matching networks of the paths comprise harmonic terminations configured to one or more of reduce an overlap between the voltage and current waveforms within the amplifier connected to the matching network and improve the linearity of one or more of the amplifiers.

An amplifier includes first, second, and third inputs to receive an RF signal, first and second amplifiers, and an input phase adjustment circuit coupling the first, second, and third inputs to the first and second amplifiers, the input phase adjustment circuit having first and second outputs coupled to the first and second amplifiers, respectively. The input phase adjustment circuit includes a pair of inputs, where the pair of inputs includes the first and second inputs, for the first output and a pair of phase adjustment paths coupling the pair of inputs to the first output, respectively. The pair of phase adjustment paths are configured to adjust a phase of the RF signal differently for the first output.

A radio-frequency signal amplifier circuit that is used in a front-end circuit configured to propagate a radio-frequency transmission signal and a radio-frequency reception signal, includes an amplifier transistor configured to amplify the radio-frequency transmission signal, a bias circuit configured to supply a bias to a signal input terminal of the amplifier transistor, a resistor having one end connected to the bias circuit and the other end connected to the signal input terminal, and an LC series resonance circuit that has one end connected to a node n1 between the resistor and the signal input terminal and the other end connected to a grounding terminal. A resonant frequency fr of the LC series resonance circuit is included in a difference frequency band between the radio-frequency transmission signal and the radio-frequency reception signal.

Multiband power amplifier with cascode switching. A power amplification system can include a first transistor having a base configured to receive an input radio-frequency (RF) signal and having an emitter coupled to a ground potential. The power amplification system can include a plurality of second transistors. Each one of the plurality of second transistors can have a respective emitter coupled to a collector of the first transistor and can be configured to, when biased at a respective base, output an output RF signal at a respective collector. The power amplification system can further include a biasing circuit configured to bias one or more of the plurality of second transistors based on a control signal.

An amplifier includes a semiconductor substrate. A first conductive feature partially covers the bottom substrate surface to define a conductor-less region of the bottom substrate surface. A first current conducting terminal of a transistor is electrically coupled to the first conductive feature. Second and third conductive features may be coupled to other regions of the bottom substrate surface. A first filter circuit includes an inductor formed over a portion of the top substrate surface that is directly opposite the conductor-less region. The first filter circuit may be electrically coupled between a second current conducting terminal of the transistor and the second conductive feature. A second filter circuit may be electrically coupled between a control terminal of the transistor and the third conductive feature. Conductive leads may be coupled to the second and third conductive features, or the second and third conductive features may be coupled to a printed circuit board.