Methods and devices used in mobile receiver front end to support multiple paths and multiple frequency bands are described. The presented devices and methods provide benefits of scalability, frequency band agility, as well as size reduction by using one low noise amplifier per simultaneous outputs. Based on the disclosed teachings, variable gain amplification of multiband signals is also presented.

A load modulated balanced amplifier (LMBA) circuit can include an input pad of the LMBA circuit configured to receive an input signal on a semiconductor die. A transformer-based hybrid splitter can be coupled to the input pad and configured to provide a first split input signal and a second split input signal from the input signal. A control power amplifier circuit coupled the first split input signal and a power amplifier circuit coupled to the second split input signal.

A bias circuit and a power amplifier circuit are provided in the present disclosure. The bias circuit includes an output node, a power detecting circuit, a first constant voltage bias circuit, and a constant current bias circuit. The output node is configured to provide a bias signal to a power amplifier unit. The output node is further configured to receive an input signal of the power amplifier unit. The power detecting circuit is configured to detect a power of the input signal of the power amplifier unit to provide a first control signal. The first constant voltage bias circuit is configured to selectively provide a first signal to the output node according to the first control signal. The constant current bias circuit provides a second signal to the output node.

A transformer-based amplifier, an operating method thereof, and devices including the same are disclosed. A millimeter wave amplifier includes a first transformer positioned on an input side of the millimeter wave amplifier, a second transformer positioned on an output side of the millimeter wave amplifier, and one or more of amplification stages positioned between the first transformer and the second transformer.

A wireless access point is configured to regularly monitor the status of WLAN, WAN and ePDG data links to determine whether the current connections are sufficient to support VoWiFI services. When a device connects to the WLAN of the hub and attempts to switch from its VoLTE service to VoWiFi via the hub, the hub is configured to determine whether the current conditions can satisfy a VoWiFi connection. If the VoWiFi service can support the connection, the request is routed to the ePDG associated with the mobile device's subscriber LTE network. However, if the current conditions cannot satisfactorily support a VoWiFi connection such that incoming calls may be missed or the quality of active calls would not be clear, then the hub is configured to block the request so that the client device will time out and remain connected to VoLTE.

A packaged RF power amplifier comprises an output network coupled to the output of a RF power transistor, which output network comprises a plurality of first bondwires extending along a first direction between the output of transistor and an output lead of the package, a series connection of a second inductor and a first capacitor between the output of the RF power transistor and ground, and a series connection of a third inductor and a second capacitor connected in between ground and the junction between the second inductor and the first capacitor. The first and second capacitors are integrated on a single passive die and the third inductor comprises a first part and a second part connected in series, wherein the first part extends at least partially along the first direction, and wherein the second part extends at least partially in a direction opposite to the first direction.

Embodiments of an RF amplifier include a transistor with a control terminal and first and second current carrying terminals, and a shunt circuit coupled between the first current carrying terminal and a ground reference node. The shunt circuit is an output pre-match impedance conditioning shunt circuit, which includes a first shunt inductance, a second shunt inductance, and a shunt capacitor coupled in series. The first shunt inductance comprises a plurality of bondwires coupled between the first current carrying terminal and the second shunt inductance, and the second shunt inductance comprises an integrated inductor coupled between the first shunt inductance and a first terminal of the shunt capacitor. The shunt capacitor is configured to provide capacitive harmonic control of an output of the transistor.

A balanced amplifier can utilize a common mode choke to suppress even harmonics in the signals of the balanced amplifier. The common choke can be coupled between cascaded balanced amplifier pairs to receive the differential output signals from one of the balanced amplifier pairs and to provide conditioned signals to the other of the balanced amplifier pairs. The common mode choke can improve the amplitude and phase balance between the differential output signals by providing increased impedance to the passage of common mode signals such as even harmonics.

In accordance with an embodiment, a circuit includes: a replica input transistor, a first replica cascode transistor, an active current source, and an active cascode biasing circuit. The active current source is configured to set a current flowing through the first replica cascode transistor and the replica input transistor to a predetermined value by adjusting a voltage of a control node of the replica input transistor; and an active cascode biasing circuit including a first output coupled to the control node of the first replica cascode transistor, and the active cascode biasing circuit configured to set a drain voltage of the replica input transistor to a predetermined voltage by adjusting a voltage of the control node of the first replica cascode transistor.

Techniques for monitoring a distortion signal of a power amplifier circuit, where the output of a distortion monitoring circuit includes little or no fundamental signal and closely represents the actual distortion of the amplifier circuit of a wired communications system. The power amplifier circuit can generate a distortion feedback signal that does not affect the power amplifier's output power capability, e.g., no inherent loss in the fundamental output of the amplifier. That is, using a distortion monitor circuit, the power amplifier circuit can resolve a distortion feedback signal from the intended output signal of the output power amplifier circuit.