Various methods and circuital arrangements for protection of an RF amplifier are presented. According to one aspect, the RF amplifier is part of switchable RF paths that include at least one path with one or more attenuators that can be used during normal operation to define different modes of operation of the at least one path. An RF level detector monitors a level of an RF signal during operation of any one of the switchable RF paths and forces the RF signal through the at least one path with one or more attenuators while controlling the attenuators to provide an attenuation of the RF signal according to a desired level of protection at an input and/or output of the RF amplifier.

An interface circuit comprises a signal path including a front-end charge amplifier coupling an input of the interface circuit to an output of the interface circuit, and a DC control loop separate from the signal path. In some implementations, the interface circuit is part of a MEMS sensor that includes a MEMS transducer having an output coupled to the input of the interface circuit. The interface circuit can, in some cases, allow faster settling of the circuit to its steady-state operating point.

An amplification system includes a first amplification module, a second amplification module, a third amplification module I, a fourth amplification module I, a first load, a third amplification module II, a fourth amplification module II and a second load. An output terminal of the first amplification module is connected to an input terminal of the second amplification module; output terminals of the second amplification module are connected to an input terminal of the third amplification module I and an input terminal of the third amplification module II. An output terminal of the third amplification module I is connected to an input terminal of the first load through the fourth amplification module I. An output terminal of the third amplification module II is connected to an input terminal of the second load through the fourth amplification module II.

Integrated circuits, such as power amplifier integrated circuits, are disclosed containing compact-footprint, vertically-integrated capacitor-avalanche diode (AD) structures. In embodiments, the integrated circuit includes a semiconductor substrate, a metal layer system, and a vertically-integrated capacitor-AD structure. The metal layer system includes, in turn, a body of dielectric material in which a plurality of patterned metal layers are located. The vertically-integrated capacitor-AD structure includes a first AD formed, at least in part, by patterned portions of the first patterned metal layer. A first metal-insulator-metal (MIM) capacitor is also formed in the metal layer system and at least partially overlaps with the first AD, as taken along a vertical axis orthogonal to the principal surface of the semiconductor substrate. In certain instances, at least a majority, if not the entirety of the first AD vertically overlaps with the first MIM capacitor, by surface area, as taken along the vertical axis.

Disclosed is an amplifier circuit for providing an output of at least 100 W, preferably of at least 200 W and most preferably of at least 250 W comprising a field effect transistor. A drain of the field effect transistor is connected with a protective feedback circuit. The protective feedback circuit is arranged to reduce an over-voltage energy at the drain of the field effect transistor if the voltage between the gate and a drain of the field effect transistor exceeds a feedback threshold voltage. Further disclosed is a radio frequency amplifier comprising an amplifier circuit, an electrical radio frequency generator comprising the radio frequency amplifier and a plasma processing system comprising an electrical radio frequency generator. Still further disclosed is a method of protecting a field effect transistor in an amplifier circuit.

An amplifier circuit includes a potential relation between a common emitter amplifier circuit (amplifier circuit body) including an NPN transistor (bipolar transistor) and a clamp circuit which maintains a potential relation between a base-collector of the NPN transistor of the common emitter amplifier circuit. The clamp circuit includes a level shift circuit and a clamp diode for suppressing a decrease in the collector potential of the NPN transistor of the common emitter amplifier circuit.

A power amplifier module includes a power amplifier circuit and a control IC. The power amplifier circuit includes a bipolar transistor that amplifies power of an RF signal and outputs an amplified signal. The control IC includes an FET, which serves as a bias circuit that supplies a bias signal to the bipolar transistor. The FET is operable at a threshold voltage lower than that of the bipolar transistor, thereby making it possible to decrease the operating voltage of the power amplifier module.

A circuit element is formed on a substrate made of a compound semiconductor. A bonding pad is disposed on the circuit element so as to at least partially overlap the circuit element. The bonding pad includes a first metal film and a second metal film formed on the first metal film. A metal material of the second metal film has a higher Young's modulus than a metal material of the first metal film.

The present invention includes a first semiconductor chip, a second semiconductor chip, a first inductor, a second inductor, a second capacitor, protective diodes, and a third inductor. A field effect transistor includes a gate terminal, a drain terminal, and a source terminal connected to a ground terminal. The second semiconductor chip includes an input terminal and an output terminal connected in a direct current manner, and includes a first capacitor connected to the input terminal and to the ground terminal. The first inductor is connected between the output terminal and the gate terminal. The second inductor includes a first terminal connected to the input terminal. The second capacitor is connected between a second terminal of the second inductor and the ground terminal. Protective diodes are connected in series in a forward direction, and each has a cathode, and an anode connected to the ground terminal. The third inductor is connected between the cathode and the second terminal.

Certain aspects of the present disclosure provide methods and apparatus for current-limiting protection of an amplifier, such as a power amplifier in a radio frequency (RF) front-end. One example current-limiting circuit generally includes a node coupled to a current source, a plurality of current-sinking devices coupled to the node, one or more switches coupled between the node and at least one of the plurality of current-sinking devices, and a bias circuit having an input coupled to the node and an output for coupling to an input of the amplifier.