An acoustic structure is provided. The acoustic structure includes an acoustic resonator structure configured to resonate in a series resonance frequency (e.g., passband frequency) to pass a signal, or cause a series capacitance to block the signal in a parallel resonance frequency (e.g., stopband frequency). The parallel resonance frequency may become higher than the series resonance frequency when the tunable capacitance is lesser than or equal to two times of the series capacitance (C.sub.Tune≤2C.sub.0), or lower than the series resonance frequency when the tunable capacitance is greater than two times of the series capacitance (C.sub.Tune>2C.sub.0). In this regard, the acoustic structure can be configured to include a tunable reactive circuit to generate the tunable capacitance (C.sub.Tune) to adjust the parallel resonance frequency. As such, it may be possible to flexibly configure the acoustic resonator structure to block the signal in desired stopband frequencies.

A multi-band power amplifier module includes at least one transmission input terminal, at least one power amplifier circuit that receives a first transmission signal and a second transmission signal through the at least one transmission input terminal, a first filter circuit that allows the first transmission signal to pass therethrough, a second filter circuit that allows the second transmission signal to pass therethrough, at least one transmission output terminal through which the first and second transmission signals output from the first and second filter circuits are output, a transmission output switch that outputs each of the first and second transmission signals output from the at least one power amplifier circuit to the first filter circuit or the second filter circuit, and a first tuning circuit that adjusts impedance matching between the at least one power amplifier circuit and the at least one transmission output terminal.

A receiver front end 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 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 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.

Loss in a low-pass filter is reduced. A radio-frequency module includes an antenna terminal, a power amplifier, a low-noise amplifier, and a low-pass filter. The low-pass filter is disposed on a transmit path between the antenna terminal and the power amplifier and on a receive path between the antenna terminal and the low-noise amplifier. The low-pass filter has multiple paths. Each of the paths forms a part of either one or both of the transmit path and the receive path. The paths include a first path and a second path. The second path has a smaller reactance than the first path.

An electronic device may include wireless circuitry with a baseband processor, a transceiver, and an antenna. The transceiver may include a mixer that outputs signals to a transimpedance amplifier. The mixer has an output impedance that varies depending on the frequency of operation. An adjustable resistance can be coupled to the input of the transimpedance amplifier. A control circuit can tune the adjustable resistance to compensate for changes in the output impedance of the mixer as the transceiver operates across a wide range of frequencies.

A transmission/reception module includes a substrate including a transmission signal input terminal, a reception signal output terminal, and an antenna terminal, an antenna switch circuit provided on the substrate and configured to output a transmission signal input from the transmission signal input terminal to the antenna terminal and configured to output a reception signal input from the antenna terminal to the reception signal output terminal, and a first inductor included in an input/output filter circuit provided between the antenna switch circuit and the antenna terminal. The first inductor includes a conductor whose winding axis direction is orthogonal to the substrate.

Aspects of the disclosure include a power amplifier comprising an input to receive an input signal, an output to provide an amplified output signal, a balun coupled between the input and the output, at least one capacitor coupled to the balun, and a controllable load coupled to the at least one capacitor.

A reactance cancelling radio frequency (RF) circuit array is disclosed. The reactance cancelling RF circuit array includes multiple RF circuits each coupled to one or two adjacent RF circuits by one or two pairs of coupling mediums each having a respective length less than one-quarter wavelength. In one aspect, an RF input signal is first split across the RF circuits and then combined to form an RF output signal. As a result, each RF circuit requires a lower power handling capability to process a portion of the RF input signal. In another aspect, each pair of the coupling mediums can cause reactance cancellation in each reactance-cancelling pair of the RF circuits. By coupling the RF circuits via the coupling mediums and enabling splitting-combining among the RF circuits, it is possible to miniaturize the reactance cancelling RF circuit array for improved performance across a wide frequency spectrum.

Programmable clamping methods and devices providing adjustable clamping powers to accommodate different applications and requirements are disclosed. The described devices can use switchable clamping circuits having different structures, body-controlled clamping circuits, or clamping circuits adjusting their input power levels using programmable resistive ladders. Examples of how the disclosed devices can be combined to improve design flexibility are also provided.

A low noise amplifier includes a first input port configured to receive a first input signal, a second input port configured to receive a second input signal, and a first amplifier stage including a first gain stage connected to the first input port and the second input port, and a first drive stage between the first gain stage and a first load circuit. The first gain stage includes a first-first gain block connected to the first input port, a first-second gain block connected to the second input port, and a first degeneration inductor between a ground terminal and a first common node of the first-first gain block and the first-second gain block. The amplifier includes a second amplifier stage including a second gain stage connected to the first input port and the second input port, and a second drive stage between the second gain stage and a second load.