A linear amplifier of an envelope tracking supply modulator includes a pre-driver stage circuit and an output stage circuit. The pre-driver stage circuit receives an envelope input, and generates a pre-driver output according to the envelope input. The output stage circuit receives the pre-driver output, and generates an amplifier output according to the pre-driver output. The amplifier output is involved in setting a modulated supply voltage of a power amplifier. The output stage circuit has a plurality of amplifiers, including a first amplifier and a second amplifier. When the power amplifier has a first output power level, the first amplifier is involved in setting the amplifier output, and the second amplifier is not involved in setting the amplifier output. When the power amplifier has a second output power level different from the first output power level, the first amplifier and the second amplifier are involved in setting the amplifier output.

An amplifier circuit includes an input terminal used to receive an input signal, an output terminal used to output an output signal, an amplification unit, and a phase adjustment unit. The amplification unit includes an input terminal coupled to the input terminal of the amplifier circuit, an output terminal coupled to the output terminal of the amplifier circuit, a first terminal coupled to a first voltage terminal, and a second terminal coupled to a second voltage terminal. The phase adjustment unit is coupled to the amplification unit. When the amplifier circuit is operated in a first mode, the output signal has a first phase, and when the amplifier circuit is operated in a second mode, the output signal has a second phase. A difference between the first phase and the second phase is within a predetermined range.

Methods and devices to fabricate low-cost wideband LNAs that are tunable to multiple frequency bands. Decoupling capacitors are used as part of a tuning circuit implemented at the LNA input. The capacitors are switchably selectable to also tune a signal into desired frequency bands.

A power amplifier circuit includes a first amplifier transistor having a base or gate for receiving a first signal inputted, the first signal being one balanced signal, a collector or drain for outputting a first amplified signal, and an emitter or source that is electrically connected to ground, a second amplifier transistor having a base or gate for receiving a second signal inputted, the second signal being another balanced signal, a collector or drain for outputting a second amplified signal, and an emitter or source that is electrically connected to the ground, a first variable capacitance electrically coupled between the collector or drain of the second amplifier transistor and the base or gate of the first amplifier transistor, and a second variable capacitance electrically coupled between the collector or drain of the first amplifier transistor and the base or gate of the second amplifier transistor.

An electronic circuit includes a differential output circuit that produces a differential output signal at a differential output. A primary winding of a balun has a first balun terminal coupled to a first differential output terminal, and a second balun terminal coupled to a second differential output terminal. A configurable harmonic reduction circuit includes first and second configurable shunt capacitance circuits coupled between the first differential output terminal or the second differential output terminal, respectively, and a ground reference node. A control circuit receives tuning data associated with a calibrated tuning state. The tuning data indicates a first and second calibrated capacitance values, which are unequal, for the first and second configurable shunt capacitance circuits, respectively. The control circuit controls the first configurable shunt capacitance circuit to have the first calibrated capacitance value, and controls the second configurable shunt capacitance circuit to have the second calibrated capacitance value.

A tracker circuit configured to provide a variable supply voltage to a power amplifier (PA) circuit is disclosed. The tracker circuit includes a state machine circuit comprising a plurality of states mapped in accordance with transitions associated with a mapping scheme. In some embodiments, the plurality of states of the state machine circuit identify one or more operational modes associated with the tracker circuit, wherein at least one operational mode comprises one or more voltage levels respectively associated therewith. In some embodiments, the one or more operational modes includes at least two active operational modes. In some embodiments, a transition between the one or more operational modes of the tracker circuit is controlled by a digital selection signal received from a digital communication interface associated therewith.

A circuit arrangement is provided which includes an array of stages for photon counting current to voltage conversion. Each stage includes a tunable operational transconductance amplifier and a feedback network forming a feedback loop of the operational transconductance amplifier. Each stage is configured to provide an output signal as a function of an input signal that is provided to the amplifier input of the operational transconductance amplifier, wherein the input signal comprises one or more current pulses and the output signal comprises one or more voltage pulses. With the tunable operational transconductance amplifier the transconductance of a stage can be tuned so that differences in peaking time and gain are avoided. Furthermore, an imaging device and a method for operating a circuit arrangement are provided.

An amplifier for a receiver circuit is disclosed. The amplifier has an input node (V.sub.in) and an output node (V.sub.out). It comprises a tunable tank circuit connected to the output node (V.sub.out), a feedback circuit path connected between the output node (V.sub.out) and the input node (V.sub.in), and a tunable capacitor connected between an internal node of the feedback circuit path and a reference-voltage node. A receiver circuit and a communication apparatus is disclosed as well.

A tunable filter is described where the frequency response as well as bandwidth and transmission loss characteristics can be dynamically altered, providing improved performance for transceiver front-end tuning applications. The rate of roll-off of the frequency response can be adjusted to improve performance when used in duplexer applications. The tunable filter topology is applicable for both transmit and receive circuits. A method is described where the filter characteristics are adjusted to account for and compensate for the frequency response of the antenna used in a communication system.

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.