In one embodiment, an apparatus comprising a first resistor, the first resistor comprising a first type of resistor having a plurality of metal wires in respective layers, the plurality of metal wires arranged in series via a plurality of vias.

A combination amplifier can include a “main amplifier circuit” for signal amplification, and a matching “compensation amplifier circuit” to monitor distortion in the main amplifier output signal. The compensation amplifier circuit provides a compensation signal to the main amplifier circuit to compensate for and servo out distortion therein. The compensation amplifier circuit includes a passive input network and an amplifier. The passive input network can connect to both the input and output nodes of the main amplifier circuit such that the input and output signals cancel within the passive input network, leaving only the low level distortion component introduced in the main amplifier. Thus, the compensation amplifier is then only operating on the low-level distortion introduced in the main amplifier to generate the compensation signal. Because the compensation amplifier is then only operating on the very low distortion signal, any distortion it introduces into the compensation signal is negligible.

A circuit and method for an audio op-amp that is configured to minimize crossover distortion between push and pull components of the audio op-amp. The audio op-amp includes an input stage that receives differential input signals and generates an output that amplifies the difference between the input signals. The audio op-amp further includes an output stage that receive the amplified signal and generate an audio output signal for playback by a speaker system. The output stage includes a diamond driver circuit that buffers the input stage from the speaker system, a boost circuit that includes a pair of boosting transistors that amplify the current of the amplified signal, and a biasing circuit that provides bias currents to the transistors of the boost circuit in a manner that minimizes crossover distortion between the boosting transistors.

An amplifier circuit includes a primary differential amplifier circuit connected to receive a differential input and provide a primary differential output with a first non-linearity. A secondary differential amplifier circuit is connected to receive the differential input. The secondary differential amplifier circuit is configured to generate a secondary differential output with a second non-linearity. The secondary differential output and the primary differential output are coupled together with opposing polarities such that the second non-linearity cancels out at least the first non-linearity.

A differential-follower control circuit has been provided, comprising: a follower; an output-voltage following module, which controls a voltage at a control terminal of the follower to vary with an output voltage; a substrate-voltage following module, which controls a substrate voltage of an output transistor of the follower to vary with an input voltage; an output terminal of the follower is connected to a first terminal of the output-voltage following module; a second terminal of the output-voltage following module is connected to the control terminal of the follower; a first terminal of the substrate-voltage following module is connected to an input terminal of the follower and a second terminal of the substrate-voltage following module is connected to a substrate of the output transistor; the invention effectively improves the overall linearity of the follower.

The present disclosure relates to semiconductor structures and, more particularly, to a differential circuit with automatic parasitic neutralization and gain boost and methods of manufacture. The structure includes a plurality of auxiliary circuit devices with back-gate controls to perform a boost gain, and a differential pair of circuit devices which are connected to the auxiliary circuit devices.

Provided herein are amplifiers, such as buffers, with increased headroom. An amplifier stage includes a follower transistor and current source configured to receive a power supply voltage comprising an alternating current component and a direct current component. The alternating current component of the power supply voltage has substantially the same frequency and magnitude as the input signal received by the follower transistor. In radio frequency (RF) and intermediate frequency (IF) buffer applications, for example, the increased headroom can allow for linear buffering of an input signals with increased amplitude so that the output power one decibel (OP1dB) compression point can be increased.

A digital-to-analog converter (DAC) circuit includes a pair of output stages, each including a DAC configured to convert a digital audio signal into an analog audio signal. A low-pass filter circuit includes an operational amplifier in signal communication with the DAC. The operation amplifier generates a filtered analog signal based on the analog audio signal. An amplifier network generates an amplified audio signal based on the filtered analog signal. The operational amplifier includes a feedback circuit path including a first node connected to the output of the amplifier network and a second node connected to the input of the operational amplifier. The amplifier network is electrically nested in the feedback circuit path.

LNA circuitry includes an input node, and output node, a primary amplifier stage, a first ancillary amplifier stage, and an input gain selection switch. The primary amplifier stage is configured to provide a first gain response between a primary amplifier stage input node and a primary amplifier stage output node, wherein the primary amplifier stage input node is coupled to the input node and the primary amplifier stage output node is coupled to the output node. The first ancillary amplifier stage is configured to provide a second gain response between a first ancillary amplifier stage input node and a first ancillary amplifier stage output node, wherein the first ancillary amplifier stage output node is coupled to the primary amplifier stage output node. The input gain selection switch is coupled between the input node and the first ancillary amplifier stage input node.

To provide a high-frequency circuit and a communication device by which a harmonic component in differential amplification can be attenuated. The high-frequency circuit includes a differential amplifier circuit. The differential amplifier circuit includes a first amplifying element, a second amplifying element, first wiring, second wiring, and a series circuit. The first amplifying element includes a first input terminal and a first output terminal. The second amplifying element includes a second input terminal and a second output terminal. The first wiring is connected to the first output terminal. The second wiring is connected to the second output terminal. The series circuit is connected between the first wiring and the second wiring. The series circuit includes a first inductor, a second inductor, and a capacitor.