A push-pull amplifier includes a pair of active devices driving the primary side of a double distributed active transformer (DDAT). The primary side of the DDAT includes a cascaded arrangement of primary windings of a first set of transformers with the active devices coupled ends of cascaded arrangement of primary windings. The secondary side of the DDAT includes a cascaded arrangement of secondary windings of a second set of transformers coupled to a load. Secondary windings of the first set of transformers drive inputs of respective active stages. Outputs of the active stages drive respective primary windings of the second set of transformers.

An apparatus includes: first and second transistors, each of the first and second transistors includes a gate terminal, a source terminal, and a drain terminal; and a transformer including a primary winding and first and second secondary windings, the primary winding is coupled to a first input node configured to receive an input signal and a second input node configured to receive a potential, the first and second secondary windings are coupled to gate terminals of the first and second transistors and cross-coupled to source terminals of the first and second transistors.

An apparatus includes a differential amplifier. The differential amplifier includes a first side circuit configured to receive a first input signal, a second side circuit configured to receive a second input signal, and a resonant tank circuit coupled between the first and second side circuits. A first capacitor and first switch may be provided in series between a source and drain of a cascode transistor. A second capacitor and second switch may be provided in series between a source and drain of an input transistor. A method includes receiving a first input signal by a first side circuit, receiving a second input signal by a second side circuit, controlling a resource of a resonant tank circuit, and outputting an output signal according to the first and second input signals. The resource of the resonant tank circuit may be controlled according to a transmission mode, frequency band, or both.

A heterojunction bipolar transistor (HBT) hybrid type RF (radio frequency) power amplifier includes a first device including an input terminal for receiving an RF signal, a pre-driver stage for amplifying the received RF signal, and an output terminal, the input terminal, the pre-driver stage and the output terminal being disposed in or over a first substrate; and a second device having a main stage having an HBT amplifier circuit disposed in or over a second substrate to further amplify the RF signal amplified by the pre-driver stage. The RF signal further amplified by the main stage is output through the output terminal of the first device.

A communication device configured to transmit/receive a radio frequency (RF) signal is provided. The device includes a transceiver including an amplifier device using a multi-loop inter-stage matching (ISM) transformer, and a processor configured to control an operation of the amplifier based on a signal strength during transmission/reception of the RF signal. The transformer is disposed between a first amplifier and a second amplifier and includes a plurality of primary loops and a plurality of secondary loops, each primary loop includes an inductor component having a different size and a different Q-factor and each secondary loop includes an inductor component having a different size and a different Q-factor. The processor adjusts an attenuation level of the transformer by controlling a switching connection to the first amplifier and the second amplifier for one primary loop among the plurality of primary loops and one secondary loop among the plurality of secondary loops.

Disclosed is an amplifier having a carrier amplifier configured as a common-emitter carrier power stage and a peaking amplifier configured as a common-emitter peaking power stage. Further included is power adaptive biasing circuitry coupled between the carrier amplifier and the peaking amplifier, wherein the power adaptive biasing circuitry is configured to sense direct current base voltages of the common-emitter carrier power stage and to generate control currents that debias the common-emitter carrier power stage in response to the current base voltages of the common-emitter carrier power stage.

An electronic device may include wireless circuitry. The wireless circuitry can include first and second input transistors, a third transistor having a gate terminal coupled to a gate terminal of the first input transistor and having a drain terminal coupled to the second input transistor, a fourth transistor having a gate terminal coupled to a gate terminal of the second input transistor and having a drain terminal coupled to the first input transistor, one or more tail circuits coupled to source terminals of the third and fourth transistors, and a bias circuit configured to output a bias voltage that is conveyed to the gate terminals of the first and second input transistors and to the one or more tail circuits. The bias circuit can be coupled to the input transistors via a coil and to the one or more tail circuits via a feedforward path.