Abstract: In an embodiment, an apparatus includes a first radio frequency (RF) signal path and a second RF signal path. The first RF signal path can provide a first RF signal when active and the second RF signal path can provide a second RF signal when active. The second RF signal path can include a select switch having an input shunt arm electrically coupled to an input of the select switch. The input shunt arm can be arranged such that it is on when the first RF signal path is active and/or when the second RF signal path is inactive.

Abstract: Disclosed are circuits and methods for reducing insertion loss effects associated with radio-frequency (RF) power couplers. In some implementations, an RF circuit can include a first path configured to route a first RF signal in a first band, and a second path configured to route a second RF signal in a second band. The RF circuit can further include a power detector having a first coupler configured to detect power along the first path, and a second coupler configured to detect power along the second path. The first coupler and the second couplers can be connected in a daisy-chain configuration. The RF circuit can further include an adjustment circuit implemented along at least one of the first path and the second paths. The adjustment circuit can be configured to move a frequency response feature associated with the power detector to a different frequency range.

Abstract: Systems, devices and methods related to improved radio-frequency (RF) modules. In some embodiments, an RF module can include a packaging substrate, a power amplifier (PA) assembly implemented on a first die mounted on the packaging substrate, and a controller circuit implemented on a second die mounted on the first die. The controller circuit can be configured to provide at least some control of the PA assembly. The RF module can further include one or more output matching network (OMN) devices mounted on the packaging substrate and configured to provide output matching functionality for the PA assembly. The RF module can further include a band selection switch device mounted on each OMN device.

Abstract: A coupler is presented that has high-directivity and low coupling coefficient variation. The coupler includes a first trace with a first edge substantially parallel to a second edge and substantially equal in length to the second edge. The first trace includes a third edge substantially parallel to a fourth edge. The fourth edge is divided into three segments. The outer segments are a first distance from the third edge. The middle segment is a second distance from the third edge. Further, the coupler includes a second trace, which includes a first edge substantially parallel to a second edge and substantially equal in length to the second edge. The second trace includes a third edge substantially parallel to a fourth edge. The fourth edge is divided into three segments. The outer segments are a first distance from the third edge. The middle segment is a second distance from the third edge.

Abstract: Apparatus and methods for reducing capacitive loading of a power amplifier supply control module are disclosed. In one embodiment, a method of power supply control in a power amplifier system includes controlling a voltage level of a supply voltage using a supply control module, amplifying a first radio frequency (RF) signal using a first power amplifier module, amplifying a second RF signal using a second power amplifier module, delivering the supply voltage to a first supply input of the first power amplifier module through a first resonant circuit, and delivering the supply voltage to a second supply input of the second power amplifier module through a second resonant circuit. The first resonant circuit includes a first inductor and a first capacitor electrically connected in parallel, and the second resonant circuit includes a second inductor and a second capacitor electrically connected in parallel.

Abstract: Disclosed are apparatus and methods related to low loss impedance transformers implemented as integrated passive devices (IPDs). In some embodiments, an IPD can include an autotransformer implemented within a body. The autotransformer can include primary and secondary metal traces implemented in respective planes separated by a distance. The autotransformer can be configured to, for example, facilitate impedance matching of radio-frequency (RF) signals. In some embodiments, the IPD can include a surface that allows mounting of one or more components thereon to provide space savings in RF modules. Examples of fabrication methods as well as products that can benefit from such IPDs are disclosed.

Abstract: Disclosed are devices and methods related to autotransformer-based impedance matching for radio-frequency (RF) applications. In some embodiments, an impedance matching device can include a primary metal trace and a secondary metal trace, each having a respective number of turns. Such metal traces can be interconnected to form an autotransformer with the primary metal trace and the secondary metal trace being in respective planes separated by a selected distance. Such an autotransformer can be utilized to, for example, facilitate impedance matching of an amplified RF signal from a power amplifier (PA). In some embodiments, the impedance matching device can be implemented as an integrated passive device (IPD) mountable on a packaging substrate. Such an IPD can be configured to allow stacking of another component on the IPD to yield a number of desirable features in products such as RF modules.

Abstract: Disclosed are circuits and methods for reducing insertion loss effects associated with radio-frequency (RF) power couplers. In some implementations, an RF circuit can include a first path configured to route a first RF signal in a first band, and a second path configured to route a second RF signal in a second band. The RF circuit can further include a power detector having a first coupler configured to detect power along the first path, and a second coupler configured to detect power along the second path. The first coupler and the second couplers can be connected in a daisy-chain configuration. The RF circuit can further include an adjustment circuit implemented along at least one of the first path and the second paths. The adjustment circuit can be configured to move a frequency response feature associated with the power detector to a different frequency range.

Abstract: Apparatus and methods for reducing capacitive loading of a power amplifier supply control module are disclosed. In one embodiment, a method of power supply control in a power amplifier system includes controlling a voltage level of a supply voltage using a supply control module, amplifying a first radio frequency (RF) signal using a first power amplifier module, amplifying a second RF signal using a second power amplifier module, delivering the supply voltage to a first supply input of the first power amplifier module through a first resonant circuit, and delivering the supply voltage to a second supply input of the second power amplifier module through a second resonant circuit. The first resonant circuit includes a first inductor and a first capacitor electrically connected in parallel, and the second resonant circuit includes a second inductor and a second capacitor electrically connected in parallel.

Abstract: Apparatus and methods for capacitive load reduction are disclosed. In one embodiment, a power amplifier system includes a power amplifier configured to amplify a radio frequency (RF) signal of a first frequency and an envelope tracker configured to control a supply voltage of the power amplifier using an envelope of the RF signal. The power amplifier system further includes an inductor electrically connected between the power amplifier and the envelope tracker and a capacitor electrically connected between the power amplifier and the envelope tracker. The capacitor and the inductor are configured to have a resonance near the first frequency.

Abstract: Apparatus and methods for oscillation suppression are disclosed. In one embodiment, a power amplifier system includes a plurality of power amplifiers for amplifying an input radio frequency (RF) signal to generate an output RF signal. The plurality of power amplifiers include a first power amplifier, a second power amplifier, and a third power amplifier, each of which are configured to be individually switchable between an enabled state and a disabled state so as to control a power amplification of the power amplifier system. A first capacitor is electrically connected between the outputs of the first and second power amplifiers, and a second capacitor is electrically connected between the outputs of the second and third power amplifiers. The first and second capacitors are configured to allow signals generated using the first, second, and third power amplifiers to combine constructively to generate the output RF signal.

Abstract: Apparatus and methods for capacitive load reduction are disclosed. In one embodiment, a power amplifier system includes a power amplifier configured to amplify a radio frequency (RF) signal of a first frequency and an envelope tracker configured to control a supply voltage of the power amplifier using an envelope of the RF signal. The power amplifier system further includes an inductor electrically connected between the power amplifier and the envelope tracker and a capacitor electrically connected between the power amplifier and the envelope tracker. The capacitor and the inductor are configured to have a resonance near the first frequency.

Abstract: Apparatus and methods for oscillation suppression are disclosed. In one embodiment, a power amplifier system includes a plurality of power amplifiers for amplifying an input radio frequency (RF) signal to generate an output RF signal. The plurality of power amplifiers include a first power amplifier, a second power amplifier, and a third power amplifier, each of which are configured to be individually switchable between an enabled state and a disabled state so as to control a power amplification of the power amplifier system. A first capacitor is electrically connected between the outputs of the first and second power amplifiers, and a second capacitor is electrically connected between the outputs of the second and third power amplifiers. The first and second capacitors are configured to allow signals generated using the first, second, and third power amplifiers to combine constructively to generate the output RF signal.