Abstract: An RF amplifier circuit includes an amplifier and a feedback circuit. The feedback circuit includes a resistive feedback circuit coupled between an input and output of the amplifier and a shunt feedback circuit coupled between the output of the amplifier and a reference input. The resistive feedback circuit includes a first set of serially coupled resistors and a first set of switches. The first sets of resistors and switches are arranged in a ladder structure with each switch of the first set of switches configured to bypass one of the resistors of the first set of resistors. The shunt feedback circuit includes a second set of serially coupled resistors and a second set of switches. The second sets of resistors and switches are arranged in a ladder structure with each switch of the second set of switches configured to bypass one of the resistors of the second set of resistors.

Abstract: In accordance with an embodiment, a system includes a switchable resistive element configured to be coupled to an input of an RF amplifier, and a switchable capacitive element having a first terminal configured to be coupled between the switchable resistive element and inductive element coupled to a system input. The switchable capacitive element is configured to reduce a first impedance of the inductive element to a second impedance lower than the first impedance during a first operation mode; the switchable resistive element is configured to reduce an input impedance of the RF amplifier to a third impedance lower than the input impedance of the RF amplifier during the first operation mode; and the switchable capacitive element and the switchable resistive element are configured to provide a first attenuation to an RF signal provided at the system input during the first operation mode.

Abstract: A multi-stage device includes multiple stages such as a first stage and a second stage. During operation, the first stage receives an input signal and outputs an intermediate signal based on the input signal. The second stage is coupled to the first stage to receive the intermediate signal and produce an output signal. According to one configuration, the second stage includes: i) a transistor, and ii) a circuit path between the first stage and the transistor. The transistor component is controlled to derive the output signal from the intermediate signal inputted to the circuit path.

Abstract: A multi-stage device includes multiple stages such as a first stage and a second stage. During operation, the first stage receives an input signal and outputs an intermediate signal based on the input signal. The second stage is coupled to the first stage to receive the intermediate signal and produce an output signal. According to one configuration, the second stage includes: i) a transistor, and ii) a circuit path between the first stage and the transistor. The transistor component is controlled to derive the output signal from the intermediate signal inputted to the circuit path.

Abstract: In accordance with an embodiment, a radio frequency (RF) amplifier circuit includes a switchable capacitance circuit having a first terminal configured to be coupled to an input matching inductor. The switchable capacitance circuit is configured to provide a short circuit between the first and second terminals in a first state, and provide a first capacitive impedance between the first and second terminals in a second state. The RF amplifier also includes a low noise amplifier (LNA) having an input terminal coupled to the second terminal of the switchable capacitance circuit; and a bypass switch coupled to an output of the LNA, the second terminal of the switchable capacitance circuit, and an output of the RF amplifier circuit. The bypass switch is configured to select the output of LNA in the first state, and select the second terminal of the switchable capacitance circuit in the second state.