For broadband data communication, a data signal voltage at a signal input node can be converted to an output signal current at a signal output node. A first transistor device can contribute to the output signal current, with its transconductance or other gain reduced to accommodate larger signal swings, at which a second transistor can turn on and increase an effective resistance value of at least a portion of a gain degeneration resistor associated with the first transistor device. The second transistor can also contribute to the output signal current to help maintain or enhance an overall gain between the signal input node and the signal output node. Multiple secondary stages, push-pull arrangements, buffer amplifier configurations (which may or may not contribute to current in the gain degeneration resistor), input and output transformers, negative feedback to help reduce component variability, and frequency modification circuits or components are also described.

An amplifier may include a differential pair circuit configured to generate an output signal according to a first input signal and a second input signal, a plurality of current sinks coupled between a ground terminal and the differential pair circuit, and a feedback circuit configured to sense a level of the output signal and generate a feedback signal. At least one of the plurality of current sinks is controlled according to the feedback signal.

An instrumentation amplifier configured for providing high common mode rejection is described and includes an input differential stage configured to receive a differential input voltage and a folded cascode amplifying stage configured to receive output current mode signals provided from the input differential pair. A plurality of feedback networks is provided to improve the input stage. The amplifier may operate to provide an enhanced common mode rejection ratio of a single gain block in the instrumentation amplifier. In some examples, the circuitry may have a differential folded cascode amplifying stage which permits high precision and low distortion of amplified signals without degrading the common mode rejection ratio.

An amplifier circuit, comprising an amplification stage, is configured to amplify an input signal, and to generate an output signal as the amplified input signal; a first feedback stage, configured to generate a first feedback voltage based on a voltage of the input signal, and to modify the output signal by the first feedback voltage; and a second feedback stage, configured to generate a second feedback voltage based on a current generated in response to the input signal, and to modify the output signal using the second feedback voltage.

A driver system includes a non-inverting system input, an inverting system input, a non-inverting system output and an inverting system output. The driver system includes a line driver which includes a non-inverting driver input coupled to the non-inverting system input and includes an inverting driver input coupled to the inverting system input. The line driver includes an inverting driver output and a non-inverting driver output. The driver system includes a first termination resistor coupled between the non-inverting driver output and the non-inverting system output and includes a second termination resistor coupled between the inverting driver output and the inverting system output. The driver system includes a first amplifier stage coupled to the line driver and includes a second amplifier stage coupled to the line driver.