A digital predistortion (DPD) system includes an input configured to receive an input signal. In some examples, a first signal path configured to generate a first signal based on the input signal. In some examples, an error model provider configured to generate an error model signal modeled after a gate bias error voltage associated with the DPD system. In some examples, a first combiner configured to combine the first signal and the error model signal to generate a first intermediate signal, and the DPD system generates an output signal based at least on the first intermediate signal.

A radio frequency amplifier includes a first input terminal, a second input terminal, an output terminal, and first and second amplifiers. The first amplifier includes a first amplifier input coupled to the first input terminal, and a first amplifier output. The second amplifier includes a second amplifier input coupled to the second input terminal, and a second amplifier output coupled to the output terminal by an output inductive element. An output combiner circuit is coupled between the first amplifier output and the second amplifier output. The output combiner circuit includes a first inductive element, a capacitor, and a second inductive element. The first inductive element is coupled between the first amplifier output and a first terminal of the capacitor, and the second inductive element is coupled between the second amplifier output and the first terminal of the capacitor. A second terminal of the capacitor is coupled to ground.

A Doherty amplifier is configured in such a way that a phase adjustment circuit adjusts either the phase of a return signal going to a first auxiliary amplification element as a result of passage of a first signal amplified by a second main amplification element through a second auxiliary amplification element as the return signal, or the phase of the return signal going to the second auxiliary amplification element as a result of reflection of the return signal by the first auxiliary amplification element, at a time of a backoff operation of the second auxiliary amplification element, in such a way that the sum of the phase of the return signal going to the first auxiliary amplification element and the phase of the return signal going to the second auxiliary amplification element is not equal to 0 degrees in the operating frequency band of the first signal.

A circuit module (e.g., an amplifier module) includes a module substrate, a thermal dissipation structure, a semiconductor die, encapsulant material, and an interposer. The module substrate has a mounting surface and a plurality of conductive pads at the mounting surface. The thermal dissipation structure extends through the module substrate, and a surface of the thermal dissipation structure is exposed at the mounting surface of the module substrate. The semiconductor die is coupled to the surface of the thermal dissipation structure. The encapsulant material covers the mounting surface of the module substrate and the semiconductor die, and a surface of the encapsulant material defines a contact surface of the circuit module. The interposer is embedded within the encapsulant material. The interposer includes a conductive terminal with a proximal end coupled to a conductive pad of the module substrate, and a distal end exposed at the contact surface of the circuit module.

A Doherty power amplifier comprising: an input configured to receive an input signal to be amplified and to split the input signal into a first portion and a second portion, the input signal having an operating frequency; a carrier amplifier path coupled to the input to receive the first portion, the carrier amplifier path including a carrier amplifier coupled to a differential inverter, the carrier amplifier being configured to amplify the first portion and provide an amplified first portion to the differential inverter, the differential inverter having a capacitance configured to make the differential inverter behave as a short circuit at odd harmonics of the operating frequency, the capacitance coupling a first path and a second path of the differential inverter in parallel; and a peaking amplifier path coupled to the input to receive the second portion and comprising a peaking amplifier configured to amplify the second portion.

Integrated circuits, such as power amplifier integrated circuits, are disclosed containing compact-footprint, vertically-integrated capacitor-avalanche diode (AD) structures. In embodiments, the integrated circuit includes a semiconductor substrate, a metal layer system, and a vertically-integrated capacitor-AD structure. The metal layer system includes, in turn, a body of dielectric material in which a plurality of patterned metal layers are located. The vertically-integrated capacitor-AD structure includes a first AD formed, at least in part, by patterned portions of the first patterned metal layer. A first metal-insulator-metal (MIM) capacitor is also formed in the metal layer system and at least partially overlaps with the first AD, as taken along a vertical axis orthogonal to the principal surface of the semiconductor substrate. In certain instances, at least a majority, if not the entirety of the first AD vertically overlaps with the first MIM capacitor, by surface area, as taken along the vertical axis.

A circuit includes a field effect transistor (FET), a reference transistor having an output coupled to an output of the FET, an active bias circuit coupled to the reference transistor and configured to generate an input signal for the reference transistor in response to a change in drain current of the reference transistor due to carrier trapping and to apply the input signal to an input of the reference transistor, and a summing node coupled to an input of the FET and to the input of the reference transistor. The summing node adds the input signal to an input signal of the FET to compensate the carrier trapping effect.

A Doherty amplifier comprising: a main-power-amplifier having a main-amp-output-terminal; a peaking-power-amplifier having a peaking-amp-output-terminal; a combining node; a main-output-impedance-inverter connected between the main-amp-output-terminal and the combining node; and a transformer connected between the peaking-amp-output-terminal and the combining node.

A Doherty amplifier circuit comprising: a splitter having: a splitter-input-terminal for receiving an input signal; a main-splitter-output-terminal; and a peaking-splitter-output-terminal; a main-power-amplifier having a main-power-input-terminal and a main-power-output-terminal, wherein; the main-power-input-terminal is connected to the main-splitter-output-terminal; and the main-power-output-terminal is configured to provide a main-power-amplifier-output-signal; a peaking-power-amplifier having a peaking-power-input-terminal and a peaking-power-output-terminal, wherein: the peaking-power-input-terminal is connected to the peaking-splitter-output-terminal; and the peaking-power-output-terminal is configured to provide a peaking-power-amplifier-output-signal. The splitter, the main-power-amplifier and the peaking-power-amplifier are provided by means of an integrated circuit.

A flip chip circuit comprising: a semiconductor substrate; a power amplifier provided on the semiconductor substrate; and a metal pad configured to receive an electrically conductive bump for connecting the flip chip to external circuitry. At least a portion of the power amplifier is positioned directly between the metal pad and the semiconductor substrate.