An RF amplifier comprises a first ‘transconductance’ transistor (N.sub.CS) arranged to receive an RF input voltage (RFIN) at its gate terminal. A second ‘cascode’ transistor (N.sub.CG) has its source terminal connected to the drain terminal of the first transistor (N.sub.CS) at a node (MID). A feedback circuit portion is configured to measure a node voltage at the node (MID), to determine an average of the node voltage, to compare said average node voltage to a predetermined reference voltage (V.sub.BCG), and to generate a control voltage (CGGATE) dependent on the difference between the average node voltage and the predetermined reference voltage (V.sub.BCG). The feedback circuit portion applies the control voltage (CGGATE) to the gate terminal of the second transistor (N.sub.CG).

Circuits and methods for achieving good AM-AM and AM-PM metrics while achieving good power, PAE, linearity, and EVM performance in an amplifier. Embodiments provide an equalization approach which compensates for AM-AM and AM-PM variations in an amplifier by controlling bias voltage versus output power to alter the AM-AM and AM-PM profiles imposed by the amplifier. Differential amplifier embodiments include cross-coupled common-gate transistors that generate an equalization voltage that alters the gate bias voltage of respective main FETs in proportion to a power level present at the respective drains of the main FETs. Single-ended amplifier embodiments include an equalization circuit that alters the bias voltage to the gate of a main FET in proportion to a power level present at the main FET drain. Embodiments may also include a linearization circuit which alters the AM-PM profile of an input signal to compensate for the AM-PM profile imposed by a coupled amplifier.

Circuits and methods for achieving good AM-AM and AM-PM metrics while achieving good power, PAE, linearity, and EVM performance in an amplifier. Embodiments provide an equalization approach which compensates for AM-AM and AM-PM variations in an amplifier by controlling bias voltage versus output power to alter the AM-AM and AM-PM profiles imposed by the amplifier. Differential amplifier embodiments include cross-coupled common-gate transistors that generate an equalization voltage that alters the gate bias voltage of respective main FETs in proportion to a power level present at the respective drains of the main FETs. Single-ended amplifier embodiments include an equalization circuit that alters the bias voltage to the gate of a main FET in proportion to a power level present at the main FET drain. Embodiments may also include a linearization circuit which alters the AM-PM profile of an input signal to compensate for the AM-PM profile imposed by a coupled amplifier.

Feedback circuit for power amplifier. In some embodiments, a radio-frequency amplifier can include a bipolar junction transistor configured to amplify a signal, and having an input and an output. The radio-frequency amplifier can further include a feedback circuit implemented between the output and input of the bipolar junction transistor. The feedback circuit can include a parallel assembly of a field-effect transistor and a resistive element such that the resistive element is bypassed when the field-effect transistor is ON and an overall resistance of the feedback circuit includes the resistive element when the field-effect transistor is OFF. Such a feedback circuit can be configured to be capable of providing a plurality of resistance values between the output and input of the bipolar junction transistor to facilitate different gains of the bipolar junction transistor.

Feedback circuit for power amplifier. In some embodiments, a radio-frequency amplifier can include a bipolar junction transistor configured to amplify a signal, and having an input and an output. The radio-frequency amplifier can further include a feedback circuit implemented between the output and input of the bipolar junction transistor. The feedback circuit can include a parallel assembly of a field-effect transistor and a resistive element such that the resistive element is bypassed when the field-effect transistor is ON and an overall resistance of the feedback circuit includes the resistive element when the field-effect transistor is OFF. Such a feedback circuit can be configured to be capable of providing a plurality of resistance values between the output and input of the bipolar junction transistor to facilitate different gains of the bipolar junction transistor.

Switchable feedback circuit for radio-frequency (RF) power amplifiers. In some embodiments, an RF power amplifier (PA) circuit can include a transistor having a base, a collector, and an emitter. The transistor can be configured to amplify an RF signal. The RF PA circuit can further include a switchable feedback circuit implemented between the collector and the base. The switchable feedback circuit can be configured to provide a plurality of resistance values between the collector and the base. Such a PA circuit can be implemented in products such as a die, a module, and a wireless device.

An amplifier operates to provide a high output impedance at an output through a push stage having a first transistor of a first transistor type and a pull stage having a second transistor of a second transistor type that is different from the first transistor type. The first transistor and the second transistor are coupled in a common-gate configuration. The first transistor and the second transistor are shorted together via a capacitor coupled to an input and share a common current path as a push-pull current-reusing common-gate low noise amplifier with a broadband input matching.

An amplifier circuit for a microphone, a microphone circuit and an electronic device are provided. The amplifier circuit includes a voltage regulator having an output terminal, a first constant current source having an input terminal connected to the output terminal of the voltage regulator, a first transistor having a gate serving as an input terminal of the amplifier circuit and a source serving as an output terminal of the amplifier circuit, a second transistor having a source connected to an output terminal of the first constant current source, a gate connected to the source of the first transistor and a drain connected to ground, a first driver configured to achieve high power supply rejection ratio of the amplifier circuit and a second driver configured to achieve high acoustic overload point of the amplifier circuit.

This disclosure provides systems, methods, and devices for wireless communication that support low noise amplification of mmWave radio frequency (RF) signals. In a first aspect, a low noise amplifier includes a first stage amplifier; a second stage amplifier; a configurable first stage bypass coupled between a first input and a first output of the first stage amplifier; and a configurable second stage bypass coupled between a second input and a second output of the second stage amplifier. Other aspects and features are also claimed and described.

This disclosure provides systems, methods, and devices for wireless communication that support low noise amplification of mmWave radio frequency (RF) signals. In a first aspect, a low noise amplifier includes a first stage amplifier; a second stage amplifier; a configurable first stage bypass coupled between a first input and a first output of the first stage amplifier, and a configurable second stage bypass coupled between a second input and a second output of the second stage amplifier. Other aspects and features are also claimed and described.