Abstract: Apparatus and methods for biasing power amplifiers are provided herein. In certain embodiments, a power amplifier includes a bipolar transistor having a base biased by a bias network having a reactance that controls an impedance at the transistor base to achieve substantially flat phase response over large dynamic power levels. For example, the bias network can have a frequency response, such as a high-pass or band-pass response, that reduces the impact of power level on phase distortion (AM/PM).

Abstract: Filters and acoustic resonators for radio-frequency circuits and devices. In some embodiments, a radio-frequency circuit can include a plurality of nodes and a common node. The radio-frequency circuit can further include a signal path implemented between each of the plurality of nodes and the common node. Each corresponding signal path can include a filter having a first Q-factor value and a respective resonator having a second Q-factor value higher than the first Q-factor value.

Abstract: Apparatus and methods for balun transformer circuits within electronic devices are provided. In certain embodiments, balun transformer circuits are used for reduction of an impedance of a differential load line of a differential power amplifier.

Abstract: Circuitry, modules, devices, and methods for integrating front-end carrier aggregation architecture are disclosed. In some embodiments, a method can include providing a packaging substrate configured to receive a plurality of components. The method can also include providing a front-end architecture implemented on the packaging substrate, the front-end architecture including a switching assembly configured to provide switching for two or more frequency bands, the switching assembly including at least one coupler configured to couple a signal associated with the switching assembly, and a diplexer circuit including a first filter configured to pass a first frequency band, a second filter configured to pass a second frequency band, and a first electrostatic discharge network configured to dissipate electrostatic energy associated with the first and second frequency bands from the front-end architecture.

Abstract: Apparatus and methods for biasing power amplifiers are provided herein. In certain embodiments, a power amplifier includes a bipolar transistor having a base biased by a bias network having a reactance that controls an impedance at the transistor base to achieve substantially flat phase response over large dynamic power levels. For example, the bias network can have a frequency response, such as a high-pass or band-pass response, that reduces the impact of power level on phase distortion (AM/PM).

Abstract: Apparatus and methods for bias switching of power amplifiers are provided herein. In certain configurations, a power amplifier system includes a power amplifier that provides amplification to a radio frequency (RF) signal and a bias control circuit that biases the power amplifier. The power amplifier includes an amplification transistor that receives the RF signal at an input, and a first bias network and a second bias network each connected to the input. The bias control circuit includes a first switch, a first reference current source that provides the first reference current to the first bias network through the first switch, a second switch, and a second reference current source that provides the second reference current to the second bias network through the second switch.

Abstract: Circuits with filters and acoustic resonators. In some embodiments, a radio-frequency circuit can include a plurality of nodes and a common node. The radio-frequency circuit can further include a signal path implemented between each of the plurality of nodes and the common node. Each corresponding signal path can include a filter having a first Q-factor value and a respective resonator having a second Q-factor value higher than the first Q-factor value.

Abstract: Circuitry, modules and devices for integrating front-end carrier aggregation architecture, are disclosed. In some embodiments, a front-end architecture includes a switching assembly configured to provide switching for two or more frequency bands. In some embodiments, the switching assembly includes at least one coupler configured to couple a signal associated with the switching assembly. The front-end architecture can also include a diplexer circuit including a first filter configured to pass a first frequency band, a second filter configured to pass a second frequency band, and a first electrostatic discharge network configured to dissipate electrostatic energy associated with the first and second frequency bands from the front-end architecture.

Abstract: In some embodiments, stability in power amplifiers can be achieved under high voltage standing wave ratio conditions, with an amplifier circuit that includes an amplifier having a selected stage among a plurality of stages, and either or both of a first stabilizing circuit implemented on an input side of the selected stage to provide stability in operation of the amplifier under a high in-band voltage standing wave ratio condition, and a second stabilizing circuit implemented on an output side of the selected stage to provide stability in operation of the amplifier under a high out-of-band voltage standing wave ratio condition.

Abstract: In some embodiments, stability in power amplifiers can be achieved under high in-band voltage standing wave ratio condition, with an amplifier circuit that includes an amplifier having a first stage and a second stage, with each stage including an input and an output, such that the output of the first stage is coupled to the input of the second stage. The amplifier circuit further includes a stabilizing circuit implemented on the input side of the second stage and configured to provide stability in operation of the amplifier under a high in-band voltage standing wave ratio condition.

Abstract: In some embodiments, stability in power amplifiers can be achieved under high out-of-band voltage standing wave ratio condition, with an amplifier circuit that includes an amplifier having a first stage and a second stage, with each stage including an input and an output, such that the output of the first stage is coupled to the input of the second stage. The amplifier circuit further includes a stabilizing circuit implemented on the output side of the second stage and configured to provide stability in operation of the amplifier under a high out-of-band voltage standing wave ratio condition.

Abstract: Apparatus and methods for reconfigurable power amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver configured to generate a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier configured to selectively amplify one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an input capacitance of the pair of amplifiers.

Abstract: Apparatus and methods for reconfigurable power amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver configured to generate a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier configured to selectively amplify one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an output capacitance of the pair of amplifiers.

Abstract: Aspects of this disclosure relate to a coupler circuit configured to receive an output of a radio frequency coupler. The coupler circuit can be arranged in a daisy chain with other coupler circuits. The coupler circuit can include a switch configured to turn on based on a signal level of a direct current component of a coupler signal from another coupler circuit and pass a radio frequency component of the coupler signal when on. The coupler circuit can pass the coupler signal while a module that includes the coupler circuit is otherwise inactive.

Abstract: Apparatus and methods for bias switching of power amplifiers are provided herein. In certain configurations, a power amplifier system includes a power amplifier that provides amplification to a radio frequency (RF) signal and a bias control circuit that biases the power amplifier. The power amplifier includes an amplification transistor that receives the RF signal at an input, and a first bias network and a second bias network each connected to the input. The bias control circuit includes a first switch, a first reference current source that provides the first reference current to the first bias network through the first switch, a second switch, and a second reference current source that provides the second reference current to the second bias network through the second switch.

Abstract: Aspects of the disclosure provide a front-end module for a wireless device comprising at least one transmit path configured to provide a first sounding reference signal, at least one transmit/receive path coupled to at least one antenna port, a sounding-reference-signal port configured to provide the first sounding reference signal and to receive a second sounding reference signal, an antenna switching module coupled between the at least one transmit path, the at least one transmit/receive path, and the sounding-reference-signal port, the antenna switching module being configured to provide the first sounding reference signal from the transmit path to the at least one transmit/receive path and the sounding-reference-signal port and to provide the second sounding reference signal received at the sounding-reference-signal port to the at least one transmit/receive path.

Abstract: Apparatus and methods for bias switching of power amplifiers are provided herein. In certain configurations, a power amplifier system includes a power amplifier that provides amplification to a radio frequency (RF) signal, a power management circuit that controls a voltage level of a supply voltage of the power amplifier, and a bias control circuit that biases the power amplifier. The power management circuit is operable in multiple supply control modes, such as an average power tracking (APT) mode and an envelope tracking (ET) mode. The bias control circuit is configured to switch a bias of the power amplifier based on the supply control mode of the power management circuit.

Abstract: Aspects of this disclosure relate to a coupler circuit configured to receive an output of a radio frequency coupler. The coupler circuit can be arranged in a daisy chain with other coupler circuits. The coupler circuit can include a switch configured to turn on based on a signal level of a direct current component of a coupler signal from another coupler circuit and pass a radio frequency component of the coupler signal when on. The coupler circuit can pass the coupler signal while a module that includes the coupler circuit is otherwise inactive.

Abstract: Apparatus and methods for biasing power amplifiers are provided herein. In certain embodiments, a power amplifier includes a bipolar transistor having a base biased by a bias network having a reactance that controls an impedance at the transistor base to achieve substantially flat phase response over large dynamic power levels. For example, the bias network can have a frequency response, such as a high-pass or band-pass response, that reduces the impact of power level on phase distortion (AM/PM).

Abstract: Apparatus and methods for biasing power amplifiers are provided herein. In certain embodiments, a power amplifier includes a bipolar transistor having a base biased by a bias network having a reactance that controls an impedance at the transistor base to achieve substantially flat phase response over large dynamic power levels. For example, the bias network can have a frequency response, such as a high-pass or band-pass response, that reduces the impact of power level on phase distortion (AM/PM).