Abstract: This disclosure relates to a mobile device with a transmission line for a radio frequency (RF) signal. The transmission line includes a bonding layer having a bonding surface, a barrier layer proximate the bonding layer, a diffusion barrier layer proximate the barrier layer, and a conductive layer proximate the diffusion barrier layer. The barrier layer and the diffusion barrier layer are configured to prevent conductive material from the conductive layer from entering the bonding layer. The diffusion barrier layer has a thickness sufficiently small such that a radio frequency signal is allowed to penetrate the diffusion barrier layer and propagate in the conductive layer.

Abstract: Fast envelope tracking systems are provided herein. In certain embodiments, an envelope tracking system for a power amplifier includes a switching regulator and a differential error amplifier configured to operate in combination with one another to generate a power amplifier supply voltage for the power amplifier based on an envelope of a radio frequency (RF) signal amplified by the power amplifier. The envelope tracking system further includes a differential envelope amplifier configured to amplify a differential envelope signal to generate a single-ended envelope signal that changes in relation to the envelope of the RF signal. Additionally, the differential error amplifier generates an output current operable to adjust a voltage level of the power amplifier supply voltage based on comparing the single-ended envelope signal to a reference signal.

Abstract: A variable load power amplifier that improves the performance of a power amplifier that provides both envelope tracking (ET) and average power tracking (APT). The variable load power amplifier can include a plurality of amplifiers that are each selectively connectable into one of a plurality of parallel combinations, each of the plurality of parallel combinations characterized by a corresponding load line. The variable load power amplifier can also include a plurality of control elements arranged to selectively connect one or more of the plurality of amplifiers into one of the plurality of parallel combinations, each of the plurality of control elements having a respective input terminal provided to receive a respective control signal, each of the plurality of control elements responsive to the respective control signal.

Abstract: Stack assembly having electro-acoustic device. In some embodiments, a radio-frequency (RF) module can include a packaging substrate configured to receive a plurality of components, and an electro-acoustic device mounted on the packaging substrate. The RF module can further include a die having an integrated circuit and mounted over the electro-acoustic device to form a stack assembly. The electro-acoustic device can be, for example, a filter device such as a surface acoustic wave filter. The die can be, for example an amplifier die such as a low-noise amplifier implemented on a silicon die.

Abstract: Fast envelope tracking systems are provided herein. In certain embodiments, an envelope tracking system for a power amplifier includes a switching regulator and a differential error amplifier configured to operate in combination with one another to generate a power amplifier supply voltage for the power amplifier based on an envelope of a radio frequency (RF) signal amplified by the power amplifier. The envelope tracking system further includes a differential envelope amplifier configured to amplify a differential envelope signal to generate a single-ended envelope signal that changes in relation to the envelope of the RF signal. Additionally, the differential error amplifier generates an output current operable to adjust a voltage level of the power amplifier supply voltage based on comparing the single-ended envelope signal to a reference signal.

Abstract: High bandwidth envelope trackers are provided herein. In certain embodiments, an envelope tracking system for a power amplifier includes a switching regulator that operates in combination with a high bandwidth amplifier to generate a power amplifier supply voltage for the power amplifier based on an envelope of a radio frequency (RF) signal amplified by the power amplifier. The high bandwidth amplifier includes an output that generates an output current for adjusting the power amplifier supply voltage, a first input that receives a reference signal, and a second input that receives an envelope signal indicating the envelope of the RF signal. The second input has lower input impedance than the first input to provide a rapid transient response and high envelope tracking bandwidth.

Abstract: Disclosed are devices and methods for improving power added efficiency and linearity of radio-frequency power amplifiers implemented in flip-chip configurations. In some embodiments, a harmonic termination circuit can be provided so as to be separate from an output matching network configured to provide impedance matching at a fundamental frequency. The harmonic termination circuit can be configured to terminate at a phase corresponding to a harmonic frequency of the power amplifier output. Such a configuration of separate fundamental matching network and harmonic termination circuit allows each to be tuned separately to thereby improve performance parameters such as power added efficiency and linearity.

Abstract: Reconfigurable antenna systems with ground tuning pads are provided herein. In certain configurations, an antenna system includes a module substrate including a ground plane and a ground tuning pad configured to receive a ground voltage from the ground plane. The antenna system further includes an antenna element and a tuning conductor that is spaced apart from the antenna element and operable to load the antenna element. Furthermore, a switch is electrically connected between the tuning conductor and the ground tuning pad, and operates to selectively connect the tuning conductor to the ground plane by way of the ground tuning pad to provide tuning to the antenna element.

Abstract: A method for manufacturing a package with a conformal shield antenna includes forming a mold compound layer, attaching the mold compound layer to a printed circuit board, applying a conformal shield layer on a first surface of the mold compound layer, the mold compound layer disposed between the conformal shield layer and the printed circuit board module, and shaping the conformal shield layer to define a planar antenna structure. Optionally, the method includes forming a cavity in the mold compound layer, applying a cover layer over the cavity to enclose the cavity and hardening the cover layer.

Abstract: An antenna structure can include a printed circuit board module and a mold compound disposed on a side of the printed circuit board module. A planar antenna is defined by a conformal shield layer disposed on a first surface of the mold compound such that the mold compound is disposed between the printed circuit board module and the conformal shield layer. The mold compound has a cavity defined therein between the planar antenna and the printed circuit board module, the cavity filled with a material different than the mold compound material. Optionally, the cavity can be filled with air. The thickness of the mold compound layer and the shape of the conformal shield layer can be varied to optimize a performance of the antenna.

Abstract: An antenna structure can include a printed circuit board module and a mold compound disposed on a side of the printed circuit board module. A planar antenna is defined by a conformal shield layer disposed on a first surface of the mold compound such that the mold compound is disposed between the printed circuit board module and the conformal shield layer. The thickness of the mold compound layer and the shape of the conformal shield layer can be varied to optimize a performance of the antenna.

Abstract: A variable load power amplifier that improves the performance of a power amplifier that provides both envelope tracking (ET) and average power tracking (APT). The variable load power amplifier can include a plurality of amplifiers that are each selectively connectable into one of a plurality of parallel combinations, each of the plurality of parallel combinations characterized by a corresponding load line. The variable load power amplifier can also include a plurality of control elements arranged to selectively connect one or more of the plurality of amplifiers into one of the plurality of parallel combinations, each of the plurality of control elements having a respective input terminal provided to receive a respective control signal, each of the plurality of control elements responsive to the respective control signal.

Abstract: One aspect of this disclosure is a power amplifier module that includes a power amplifier die, a first bonding pad on a conductive trace, and a second bonding pad on a conductive trace. The die includes an on-die passive device and a power amplifier. The first bonding pad is electrically connected to the on-die passive device by a first wire bond. The second bonding pad is in a conductive path between the first bonding pad and a radio frequency output of the power amplifier module. The second bonding pad includes a nickel layer having a thickness that is less than 0.5 um, a palladium layer over the nickel layer, and a gold layer over the palladium layer and bonded to a second wire bond that is electrically connected to an output of the power amplifier. Other embodiments of the module are provided along with related methods and components thereof.

Abstract: A variable load power amplifier that improves the performance of a power amplifier that provides both envelope tracking (ET) and average power tracking (APT). The variable load power amplifier can include a plurality of amplifiers that are each selectively connectable into one of a plurality of parallel combinations, each of the plurality of parallel combinations characterized by a corresponding load line. The variable load power amplifier can also include a plurality of control elements arranged to selectively connect one or more of the plurality of amplifiers into one of the plurality of parallel combinations, each of the plurality of control elements having a respective input terminal provided to receive a respective control signal, each of the plurality of control elements responsive to the respective control signal.

Abstract: One aspect of this disclosure is a power amplifier module that includes a power amplifier configured to amplify a radio frequency (RF) signal and an RF transmission line electrically coupled to an output of the power amplifier. The power amplifier includes a heterojunction bipolar transistor and a p-type field effect transistor, in which a semiconductor portion of the p-type field effect transistor corresponds to a channel includes the same type of semiconductor material as a collector layer of the heterojunction bipolar transistor. The RF transmission line includes a nickel layer with a thickness that is less than 0.5 um, a conductive layer under the nickel layer, a palladium layer over the nickel layer, and a gold layer over the palladium layer. Other embodiments of the module are provided along with related methods and components thereof.

Abstract: Apparatus and methods for wideband envelope tracking systems are disclosed herein. In certain implementations, an envelope tracker includes a DC-to-DC converter, a current digital-to-analog converter (DAC), an error amplifier, a feedback circuit, and an AC combiner. The current DAC receives a digital envelope signal, and uses the digital envelope signal to generate an envelope current. The feedback circuit is connected between an output and an inverting input of the error amplifier, and the envelope current is provided to the error amplifier's inverting input. Additionally, the AC combiner generates a power amplifier supply voltage by combining an output of the DC-to-DC converter and an output of the error amplifier.

Abstract: Apparatus and methods for phase compensation in power amplifiers are disclosed herein. In certain implementations, a method of phase compensation in a power amplifier includes amplifying a radio frequency signal using a power amplifier that includes an input stage and an output stage, powering a bipolar transistor of the output stage using a power amplifier supply voltage, changing a voltage level of the power amplifier supply voltage, the bipolar transistor having an input reactance that changes in response to the change in the voltage level of the power amplifier supply voltage, and compensating for a variation in a phase delay of the power amplifier arising from the change in the input reactance of the bipolar transistor using a compensation circuit that is electrically connected to an output of the input stage.

Abstract: Apparatus and methods for wireless local area network (WLAN) power amplifiers are provided. In certain configurations, a WLAN power amplifier system includes a WLAN power amplifier, an output impedance matching network, and an envelope tracker. The WLAN power amplifier includes an input that receives a WLAN signal having a fundamental frequency and an output that generates an amplified WLAN signal for transmission over an antenna. The output impedance matching network is electrically connected to the output of the WLAN power amplifier, and can provide a load line impedance between 10? and 35? at the fundamental frequency. The envelope tracker receives an envelope of the WLAN signal, and controls a voltage level of a power supply of the WLAN power amplifier based on the envelope signal.

Abstract: One aspect of this disclosure is a power amplifier module that includes a power amplifier configured to provide a radio frequency signal at an output, an output matching network coupled to the output of the power amplifier and configured to provide impedance matching at a fundamental frequency of the radio frequency signal, and a harmonic termination circuit coupled to the output of the power amplifier. The power amplifier is included on a power amplifier die. The output matching network can include a first circuit element electrically connected to an output of the power amplifier by way of a pad on a top surface of a conductive trace, in which the top surface has an unplated portion between the pad the power amplifier die. The harmonic termination circuit can include a second circuit element. The first and second circuit elements can have separate electrical connections to the power amplifier die. Other embodiments of the module are provided along with related methods and components thereof.

Abstract: This disclosure relates to a radio frequency (RF) transmission line for high performance RF applications. The RF transmission line includes a conductive layer and finish plating on the conductive layer. The finish plating includes a gold layer, a palladium layer proximate the gold layer, and a nickel layer proximate the palladium layer. The nickel layer has a thickness that allows a radio frequency signal received at the gold layer to penetrate the nickel layer and propagate in the conductive layer.