Abstract: An embodiment of an amplifier includes an amplifier output node operable to provide an output signal, and an output stage. The output stage includes a drive buffer having an input node and an output node, a drive transistor, and a compensation capacitor. The drive transistor has a control node coupled to the output node of the drive buffer, a first drive node, and a second drive node coupled to the amplifier output node. And the compensation capacitor has a first node isolated from the control node of the drive transistor by the drive buffer, and has a second node coupled to the amplifier output node. By buffering the control node of the drive transistor, one may reduce the level of nonlinear current referred back to the amplifier input as a nonlinear offset voltage, and thus may reduce the level of nonlinear distortion that his nonlinear offset voltage generates at the amplifier output.

Abstract: An embodiment of an amplifier includes an amplifier output node operable to provide an output signal, and an output stage. The output stage includes a drive buffer having an input node and an output node, a drive transistor, and a compensation capacitor. The drive transistor has a control node coupled to the output node of the drive buffer, a first drive node, and a second drive node coupled to the amplifier output node. And the compensation capacitor has a first node isolated from the control node of the drive transistor by the drive buffer, and has a second node coupled to the amplifier output node. By buffering the control node of the drive transistor, one may reduce the level of nonlinear current referred back to the amplifier input as a nonlinear offset voltage, and thus may reduce the level of nonlinear distortion that his nonlinear offset voltage generates at the amplifier output.

Abstract: Methods and circuits for extracting a true mean of two signals are provided. A first amplifier input stage (e.g., an n-type stage) is operated when a mean of the two signals approaches an upper rail voltage. A second amplifier input stage (e.g., a p-type stage) is operated when the mean of the two signals approaches a lower rail voltage. A transitioning circuit controls how much each of the first and the second amplifier input stages contributes to an input of a high-gain amplifier output stage, when the mean of the two signal does not approach either of the rail voltages. An output of the high-gain amplifier output stage is fed back to both the first and second amplifier input stages via a feedback stage, which can be a matched buffer stage.