Provided is a power amplification circuit that includes: a first transistor that has an emitter to which a first radio frequency signal is supplied, a base to which a first DC control current or DC control voltage is supplied and a collector that outputs a first output signal that corresponds to the first radio frequency signal; a first amplifier that amplifies the first output signal and outputs a first amplified signal; and a first control circuit that supplies the first DC control current or DC control voltage to the base of the first transistor in order to control output of the first output signal.

The transmission device comprising a transmit stage configured to deliver a transmission signal on an input-output node of an antenna and comprising a power transistor coupled to the input-output node and configured to amplify a signal to be transmitted. The device comprises a receive stage configured to receive a reception signal on the input-output node and comprising an attenuator circuit configured to attenuate the reception signal. The attenuator circuit comprising the power transistor and a control circuit able to place the power transistor in a triode mode.

A radio frequency (RF) power amplifier circuit includes an input and an output. A power amplifier transistor has a first terminal connected to the input, a second terminal connected to the output, and a third terminal defined by a degeneration inductance. A first capacitor is connected to the third terminal of the power amplifier transistor, along with a negative capacitance circuit connected in series with the first capacitor. The negative capacitance and the first capacitor define a series resonance at a predefined operating frequency band, which shunts the degeneration inductance of the third terminal.

Multi-band device having multiple miniaturized single-band power amplifiers. In some embodiments, a power amplifier die can include a semiconductor substrate, and a plurality of power amplifiers (PAs) implemented on the semiconductor substrate. Each PA can be configured to drive approximately a characteristic load impedance of a downstream component along an individual frequency band signal path, such that each PA is sized smaller than a wide band PA configured to drive more than one of the frequency bands associated with the plurality of PAs. The downstream component can include an output filter.

Multi-band device having multiple miniaturized single-band power amplifiers. In some embodiments, a power amplifier die can include a semiconductor substrate, and a plurality of power amplifiers (PAs) implemented on the semiconductor substrate. Each PA can be configured to drive approximately a characteristic load impedance of a downstream component along an individual frequency band signal path, such that each PA is sized smaller than a wide band PA configured to drive more than one of the frequency bands associated with the plurality of PAs. The downstream component can include an output filter.

Optimized impedance characteristics of a variable impedance device causes the apparatus to transmit wireless signals with minimal out-of-band transmission at an optimized efficiency of the power amplifier. The variation of impedance characteristics of an antenna cause a change in the coefficients of a mapping function. The relatively fast variations to the power supply voltage of a power amplifier are applied to the mapping function to generate control signals which vary the impedance characteristics of a variable impedance device. The output of the mapping function includes control signals that control optimized impedance characteristics of a variable impedance device as a function of the variation of the supply voltage to a power amplifier. The coefficients of the mapping function may be regularly determined based on a comparison of out-of-band power and in-band power transmitted by an antenna.

An RF amplifier includes a transistor, a shunt circuit, an envelope frequency termination circuit, and an extra lead. The shunt circuit is coupled between a transistor current carrying terminal and a ground reference node. The shunt circuit has a shunt inductive element and a shunt capacitor coupled in series, with an RF cold point node between the shunt inductive element and the shunt capacitor. The envelope frequency termination circuit is coupled between the RF cold point node and the ground reference node. The envelope frequency termination circuit has an envelope resistor, an envelope inductive element, and an envelope capacitor coupled in series. The extra lead is electrically coupled to the RF cold point node. The extra lead provides a lead inductance in parallel with an envelope inductance provided by the envelope inductive element. An additional shunt capacitor can be coupled between the extra lead and ground.

A packaged RF amplifier device includes a transistor, a first input circuit, and a second input circuit. The first input circuit includes a first series inductance coupled between an input lead and a first node, a second series inductance coupled between the first node and the transistor's control terminal, and a first shunt capacitance coupled between the first node and a ground reference. The second input circuit includes a first shunt inductance and a second shunt capacitance coupled in series between the input lead and the ground reference. The first input circuit and the second input circuit create a fundamental frequency match for the device. The second series inductance and the first shunt capacitance present a short circuit to the ground reference for RF energy at a second harmonic frequency.

An envelope tracking amplifier having stacked transistors is presented. The envelope tracking amplifier uses dynamic bias voltages at one or more gates of the stacked transistors in addition to a dynamic bias voltage at a drain of a transistor.

An envelope tracking amplifier having stacked transistors is presented. The envelope tracking amplifier uses dynamic bias voltages at one or more gates of the stacked transistors in addition to a dynamic bias voltage at a drain of a transistor.