A power amplifying circuit includes a first input terminal applied with a first bias voltage, a first amplifying circuit generating a first output signal and a second output signal according to an input signal and a first matching circuit combining the first output signal and the second output signal to generate an output signal. The first amplifying circuit includes a first transistor having a first electrode coupled to the first input terminal and a second electrode applied with a second bias voltage and a second transistor having a first electrode s coupled to the first input terminal and a second electrode applied with a third bias voltage. The first transistor generates the first output signal according to the first bias voltage and the second bias voltage. The second transistor generates the second output signal according to the first bias voltage and the third bias voltage.

An impedance matching circuit includes a radiofrequency terminal and a series circuit connected to the radiofrequency terminal, wherein the series circuit comprises at least one reactance and at least one switching element having a drive input. A drive circuit is connected to the drive input and a coupler is connected to the drive circuit so as to an enable signal input. The impedance matching circuit enables short switching times and low losses in the at least one switching element.

Disclosed is an amplifying circuit and method. In one embodiment, an amplifying circuit, includes: a common-gate (CG) amplifier, wherein the CG amplifier comprises a first transistor, wherein source terminal and body terminal of the first transistor is coupled together through a first resistor.

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.

Disclosed is an amplifying circuit and method. In one embodiment, an amplifying circuit, includes: a common-gate (CG) amplifier, wherein the CG amplifier comprises a first transistor, wherein source terminal and body terminal of the first transistor is coupled together through a first resistor.

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 current feedback amplifier (CFA). The CFA includes a common-gate input stage, a biasing circuitry, and a differential pair coupled in parallel between the supply voltage node and the reference voltage node. The common-gate input stage amplifies an input signal received at an input node and supplies it to a gate of the complementary transistors of the differential pair. The biasing circuitry supplies a bias voltage to a gate of the transistors of the common-gate input stage. The input node of the common-gate input stage and a node between the complementary transistors in the first path of the differential pair are shorted.

A power amplifier includes a common source amplifier and a common gate amplifier circuit. The common source amplifier circuit has a terminal connected to a radio frequency (RF) input terminal and uses a source terminal commonly as an input terminal and an output terminal of the power amplifier. The common gate amplifier circuit has a terminal connected to the common source amplifier circuit and another terminal connected to an RF output terminal, and uses a gate terminal commonly as the input terminal and the output terminal of the power amplifier. The common gate amplifier circuit includes a Doherty amplifier including a main power amplifier and an auxiliary power amplifier that is connected to the main power amplifier in parallel.

Provided herein are amplifiers, such as buffers, with increased headroom. An amplifier stage includes a follower transistor and current source configured to receive a power supply voltage comprising an alternating current component and a direct current component. The alternating current component of the power supply voltage has substantially the same frequency and magnitude as the input signal received by the follower transistor. In radio frequency (RF) and intermediate frequency (IF) buffer applications, for example, the increased headroom can allow for linear buffering of an input signals with increased amplitude so that the output power one decibel (OP1dB) compression point can be increased.

A balanced differential transimpedance amplifier with a single-ended input operational over a wide variation in the dynamic range of input signals. A threshold circuit is employed to either or a combination of (1) generate a varying decision threshold to ensure a proper slicing over a wide range of input current signal levels; and (2) generate a bias current and voltage applied to an input of a transimpedance stage to cancel out a dependence of the transimpedance stage voltage input on input current signal levels.