In accordance with an embodiment, a method for operating a millimeter-wave power amplifier including an input transistor having an output node coupled to a load path of a cascode transistor includes: receiving a millimeter-wave transmit signal at a control node of the input transistor; amplifying the millimeter-wave transmit signal to form an output signal; providing the output signal to a load coupled to an output node of the cascode transistor; and adjusting a first DC bias current of the input transistor to form a substantially constant second DC bias current of the cascode transistor.

An acoustic wave device includes a piezoelectric substrate including a support substrate and a piezoelectric layer on the support substrate, the piezoelectric substrate including a first principal surface on the piezoelectric layer side, and a second principal surface on the support substrate side, an IDT electrode on the first principal surface, a support layer on the support substrate, a cover on the support layer, a through-via electrode provided through the support substrate and electrically connected to the IDT electrode, a first wiring electrode on the second principal surface of the piezoelectric substrate and electrically connected to the through-via electrode, and a protective film on the second principal surface to cover at least a portion of the first wiring electrode. The protective film is provided on an inner side of the support layer when viewed in a direction normal or substantially normal to the second principal surface.

A radio frequency module includes: a module board that includes a first principal surface and a second principal surface on opposite sides of the module board; a power amplifier configured to amplify a transmission signal; a first circuit component; and a power amplifier (PA) control circuit configured to control the power amplifier. The power amplifier and the PA control circuit are stacked on the first principal surface, and the first circuit component is disposed on the second principal surface.

Circuits and methods for achieving good amplifier AM-AM and AM-PM metrics while achieving good power, PAE, linearity, and EVM performance. Embodiments compensate for a non-linear distortion profile (e.g., an AM-PM and/or AM-AM profile) in an amplifier by pre-processing an input signal, such as a radio-frequency signal, to alter the non-linear distortion profile of the input signal so as to compensate for the non-linear distortion profile imposed by a coupled device, such as an amplifier. An inventive aspect includes linearizing an output from an amplifier having a first non-linear distortion profile, including passing an input signal having a second non-linear distortion profile through a reflective hybrid coupler to a non-linear termination circuit, and reflecting a modified input signal from the non-linear termination circuit back through the reflective hybrid coupler as an output signal, the output signal having a third non-linear distortion profile shaped to compensate for the first non-linear distortion profile.

Methods and circuital arrangements for turning OFF branches of a multi-branch cascode amplifier are presented. First and second switching arrangements coupled to a branch allow turning OFF the branch while protecting transistors of the branch from a supply voltage that may be greater than a tolerable voltage of the transistors. The first switching arrangement includes a transistor-based switch that is in series connection with the transistors of the branch. The first switching arrangement drops the supply voltage during the OFF state of the branch and provides a conduction path for a current through the branch during the ON state of the branch. A resistor and a shunting switch are coupled to a gate of the transistor-based switch to reduce parasitic coupling effects of the transistor-based switch upon an RF signal coupled to the branch during the ON state and OFF state of the branch.

Microwave amplifiers tolerant to electrical overstress are provided. In certain embodiments, a monolithic microwave integrated circuit (MMIC) includes a signal pad that receives a radio frequency (RF) signal, a ground pad, a balun including a primary section that receives the RF signal and a secondary section that outputs a differential RF signal, an amplifier that amplifies the differential RF signal, and a plurality of decoupling elements, some of them electrically connected between the primary section and the ground pad, others electrically connected in the secondary section to a plurality of the amplifier's nodes, and operable to protect the amplifier from electrical overstress. Such electrical overstress events can include electrostatic discharge (ESD) events, such as field-induced charged-device model (FICDM) events, as well as other types of overstress conditions.

A semiconductor device includes input and output terminals, first and second power supply terminals, first and second transistors, and a first resistance element. In the first transistor, gate and source terminals are respectively connected to the input terminal and the first power supply terminal, a drain terminal is connected to the second power supply terminal in direct current and to the output terminal, and the gate and drain terminals are connected via the first resistance element. In the second transistor, a source terminal is connected to the first power supply terminal, and gate and drain terminals are short-circuited at a node connected to the gate terminal of the first transistor in direct current. In a lower frequency region, an impedance of the first resistance element is lower than impedances of parasitic capacitances in the first transistor between the gate and drain terminals and between the gate and source terminals.

A power amplification circuit may comprise a power distributor configured to receive a radio frequency (RF) signal and output a first RF signal and a second RF signal, a first power amplifier configured to receive the first RF signal from the power distributor and amplify the first RF signal based on a first bias, a second power amplifier configured to receive the second RF signal from the power distributor and amplify the second RF signal based on a second bias, an impedance matching circuit configured to receive the first RF signal amplified by the first power amplifier and the second RF signal amplified by the second power amplifier, and a protection circuit configured to identify a current input to a bias terminal of the second power amplifier and, control a magnitude of the current input to the bias terminal based on the identified input current.

A low noise amplifier for an RF sampling analog front end. The amplifier includes digital step attenuation for applying a selected attenuation to signals received at an input node, and a gain stage coupled to amplify the attenuated signal from the digital step attenuation circuit. In a differential amplifier implementation, a first input capacitor is coupled between a positive side input node and an output of the negative side digital attenuation circuit, and a second input capacitor is coupled between a negative side input node and an output of the positive side digital step attenuation circuit. In some embodiments, variable feedback circuits are coupled between each input node and an output of the corresponding gain stage, to selectively apply active termination at the input at high gain settings of the amplifier. Variable input and output resistors, and programmable noise filtering at the output, are provided in some embodiments.

A front-end module may include an acoustic wave filter with a first and second interdigital transducer electrode, and a low noise amplifier (LNA) that converts a differential input to a single-ended output with respect to ground. The first interdigital transducer electrode may be single-ended with a first input bus bar configured to receive an input signal and a second input bus bar connected to ground. The second interdigital transducer electrode may be differential with a first output bus bar connected to a first output terminal and a second output bus bar connected to a second output terminal. The LNA may have a differential input connected to the acoustic wave filter, a first input transistor that receives a first signal from the first output terminal of the acoustic wave filter, and a second input transistor that receives a second signal from the second output terminal of the acoustic wave filter.