According to an aspect, there is provided a comparator comprising input terminals, first, second and third biasing current sources configured to output first, second and third biasing currents, an input circuit driven by the first biasing current source and comprising an amplification circuit and a load circuit configured to provide positive feedback for the amplification circuit, first and second current mirroring circuits for forming, with the input circuit, first and second current mirrors producing first and second current mode signals, first and second current-controlled driver circuits configured to be controlled by the second and third biasing currents, respectively, and the first and second current mode signals, respectively, a latch circuit comprising first and second cross-coupled complementary metal-oxide semiconductor transistors acting as a latch having substantially rail-to-rail output voltage swing and being driven, respectively, by the first and second current-controlled driver circuits and an output circuit implementing a current starved inverter.

An apparatus includes a preamplifier stage to receive a power supply voltage and generate an output based upon an input. In particular, the preamplifier stage includes a biasing device coupled between the output and a ground node to bias a DC voltage level of the output independently of the power supply voltage. The preamplifier stage also includes a complementary circuit to receive the input and generate the output. The complementary circuit reuses a current through the preamplifier stage to provide an increased transconductance of the preamplifier stage for a given current level.

Hybrid variable gain amplifiers and methods of controlling hybrid VGAs are disclosed. The hybrid VGA includes a first portion that provides a current path between a positive input and a positive output, and a current path either between the positive input and a negative output, in a first mode of operation, or between the positive input and a voltage source, in a second mode of operation. A second portion of the VGA provides a current path between a negative input and the negative output, and a current path either between the negative input and the positive output, in the first mode of operation, or between the negative input and the voltage source, in the second mode of operation. Control voltages selectively enable the paths in the first or second mode of operation. The control voltages further control amount of current flow in the enabled paths.

A voltage-to-current converter that reduces third harmonic distortion. An amplifier includes an input stage. The input stage includes a first voltage-to-current conversion stage and a second voltage-to-current conversion stage. The first voltage-to-current conversion stage is configured to provide an input to output gain with compressive nonlinearity. The second voltage-to-current stage is cascaded with the first voltage-to-current conversion stage. An input of the second voltage-to-current stage is connected to an output of the first voltage-to-current conversion stage. The second voltage-to-current conversion stage is configured to provide an input to output gain with expansive nonlinearity.

A power amplifier with supply switching is provided. The power amplifier detects a magnitude of an outgoing broadband communication signal and determines whether the magnitude exceeds a predetermined voltage threshold. The power amplifier applies a first gain to the outgoing broadband communication signal using a first voltage supply rail when it is determined that the magnitude exceeds the predetermined voltage threshold and a second gain using a second voltage supply rail that is smaller than the first voltage supply rail when it is determined that the magnitude does not exceed the predetermined voltage threshold. The power amplifier produces an output signal from the outgoing broadband communication signal with the applied first gain or the applied second gain, wherein a current of the outgoing broadband communication signal is switched between the first voltage supply rail and the second voltage supply rail in response to the magnitude being detected.

An amplifier includes a first stage and a second stage. The first stage includes a first output and a second output. The second stage includes an output, a first transistor and a second transistor. The first transistor includes a drain coupled to the first output of the first stage, and a source coupled to the output of the second stage. The second transistor includes a drain coupled to the second output of the first stage, and a gate coupled to the output of the second stage.

Certain aspects of the present disclosure generally relate to using cross-coupled transistors for source degeneration of an amplification stage. For example, the amplification stage generally includes a differential amplifier comprising transistors, cross-coupled transistors coupled to the differential amplifier, and an impedance coupled between drains of the cross-coupled transistors. In certain aspects, the differential amplifier comprises a push-pull amplifier, and the transistors of the push-pull amplifier comprise cascode-connected transistors.

A two-stage circuit includes a differential-to-single-ended first stage with a differential pair of transistors. The first stage includes a current mirror including a diode-connected transistor having an RC circuit coupled to a drain of the diode-connected transistor. The current mirror is configured to mirror a power supply noise current conducted by the RC circuit through a first stage output terminal to a gate of an output transistor in a second stage of the two-stage circuit.

An operational amplifier comprises: a first amplifier stage 4 comprising a first differential pair of transistors 8, 10 arranged to receive and amplify a differential input signal 18, 20 thereby providing a first differential output signal 22, 24; and a second amplifier stage 6 comprising a second differential pair of transistors 26, 28 arranged to receive and amplify the first differential output signal 22, 24 thereby providing a second differential output signal 38, 40.

A power amplifier with supply switching is provided. The power amplifier detects a magnitude of an outgoing broadband communication signal and determines whether the magnitude exceeds a predetermined voltage threshold. The power amplifier applies a first gain to the outgoing broadband communication signal using a first voltage supply rail when it is determined that the magnitude exceeds the predetermined voltage threshold and a second gain using a second voltage supply rail that is smaller than the first voltage supply rail when it is determined that the magnitude does not exceed the predetermined voltage threshold. The power amplifier produces an output signal from the outgoing broadband communication signal with the applied first gain or the applied second gain, wherein a current of the outgoing broadband communication signal is switched between the first voltage supply rail and the second voltage supply rail in response to the magnitude being detected.