Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are possible where the amplifier is configured to operate in at least an active mode and a standby mode. Circuital arrangements can reduce bias circuit standby current during operation in the standby mode while allowing a quick recovery to normal operating conditions of the amplifier. Biasing an input transistor of the stacked transistors can be obtained by using a replica stack circuit.

A receiver front end (300) having low noise amplifiers (LNAs) is disclosed herein. A cascode having a “common source” configured input FET and a “common gate” configured output FET can be turned on or off using the gate of the output FET. A first switch (235) is provided that allows a connection to be either established or broken between the source terminal of the input FET of each LNA. A drain switch (260) is provided between the drain terminals of input FETs to place the input FETs in parallel. This increases the g.sub.m of the input stage of the amplifier, thus improving the noise figure of the amplifier.

Methods and apparatus for providing amplifier protection for a radio frequency (RF) front-end circuit. An example RF front-end circuit generally includes an amplifier with a gain, a first sensor configured to sense a first power (or voltage) of a first node coupled to an input of the amplifier, a second sensor configured to sense a second power (or voltage) of a second node coupled to an output of the amplifier, and logic coupled to the first and second sensors. The logic is generally configured to determine that the second power (or voltage) is outside a range based on the gain and the first power (or voltage) and to take an action to protect the amplifier based on the determination. By utilizing the techniques and apparatus described herein, protection can be provided to the amplifier(s) in an RF front-end circuit without significantly impacting the performance of the RF front-end circuit.

Circuits, devices and methods related to amplification with active gain bypass. In some embodiments, an amplifier can include a first amplification path implemented to amplify a signal, and having a cascode arrangement of a first input transistor and a cascode transistor to provide a first gain for the signal when in a first mode. The amplifier can further include a second amplification path implemented to provide a second gain for the signal while bypassing at least a portion of the first amplification path when in a second mode. The second amplification path can include a cascode arrangement of a second input transistor and the cascode transistor shared with the first amplification path. The amplifier can further include a switch configured to allow routing of the signal through the first amplification path in the first mode or the second amplification path in the second mode.

In an embodiment, a differential buffer may include a first input stage that compares a non-inverting portion of an input signal alternately to a non-inverting portion of an output and to an inverting portion of the output. Another embodiment of the differential buffer may also include a second input stage that compares the inverting portion of the input signal alternately to the inverting portion of the output signal and to the non-inverting portion of the output signal. Other embodiments of the differential buffer may include a feedback chopper switch that transfers the non-inverting portion of the output signal and the inverting portion of the output signal to the first input stage and to the second input stage.

Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are possible where the amplifier is configured to operate in at least an active mode and a standby mode. Circuital arrangements can reduce bias circuit standby current during operation in the standby mode while allowing a quick recovery to normal operating conditions of the amplifier. Biasing an input transistor of the stacked transistors can be obtained by using a replica stack circuit.

In an embodiment, a differential buffer may include a first input stage that compares a non-inverting portion of an input signal alternately to a non-inverting portion of an output and to an inverting portion of the output. Another embodiment of the differential buffer may also include a second input stage that compares the inverting portion of the input signal alternately to the inverting portion of the output signal and to the non-inverting portion of the output signal. Other embodiments of the differential buffer may include a feedback chopper switch that transfers the non-inverting portion of the output signal and the inverting portion of the output signal to the first input stage and to the second input stage.

A low noise amplifier has a first transistor that amplifies a high frequency input signal, a second transistor that further amplifies the amplified signal to generate an output signal, a first inductor connected between the source of the first transistor and a first reference potential node, a third transistor that is connected between the source of the first transistor and the first inductor, a first capacitor and a first resistor connected in series between a drain of the second transistor and an output node of the low noise amplifier, a second resistor and a third resistor connected in series between a gate of the third transistor and a second reference potential node, and a charge pump circuit that sets a potential of a connection node between the second resistor and the third resistor to a potential lower than a potential of the first reference potential node in the second mode.

A radio frequency circuit includes a switching circuit, an amplifying circuit, and a potential stabilizing circuit. The switching circuit includes a switch disposed on a path connecting a first terminal, to which a radio-frequency signal is input, to a second terminal, from which the radio-frequency signal is output, a first capacitor disposed between the first terminal and the switch, and a second capacitor disposed between the switch and the second terminal. The amplifying circuit includes an amplifier disposed between the switching circuit and the second terminal, a third capacitor disposed between the switching circuit and the amplifier, and a fourth capacitor disposed between the amplifier and the second terminal. The potential stabilizing circuit is connected to a first node which is located between the switching circuit and the amplifying circuit and which is located on a path connecting the second capacitor to the third capacitor.

A radio frequency module includes a mounting substrate, a low-noise amplifier including an amplifying element and amplifying a radio frequency signal, and an impedance matching circuit including an integrated first inductor, in which the first inductor is connected to an input terminal of the low-noise amplifier, the low-noise amplifier and the impedance matching circuit are laminated in a direction perpendicular to a main surface of the mounting substrate, and a first multilayer body on which the low-noise amplifier and the impedance matching circuit are laminated is mounted on the main surface.