In accordance with aspects of the present invention, embodiments of a photodiode circuit. A photodiode circuit according to some embodiments includes a transimpedance amplifier; a resistor coupled across the transimpedance amplifier; and an amplifier stage coupled to receive an output from the transimpedance amplifier, wherein the photodiode circuit provides dynamic range across a current range of the photodiode circuit. In some embodiments, the transimpedance amplifier includes a receive signal strength indicator that provides a DC current signal to a tail of a first amplifier stage, the tail providing a current that is adaptively related to the DC current. In some embodiments, the resistor is a shielded resistor. In some embodiments, the adaptive current sink includes a plurality of switchable parallel current sinks.

A power amplifier circuit for broadband data communication over a path in a communication network can reduce or avoid gain compression, provide low distortion amplification performance, and can accommodate a wider input signal amplitude range. A dynamic variable bias current circuit can be coupled to a differential pair of transistors to provide a dynamic variable bias current thereto as a function of input signal amplitude. Bias current is increased when input signal amplitude exceeds a threshold voltage established by an offset or level-shifting circuit. The frequency response of the bias current circuit can track the full frequency content of the input signal, rather than its envelope. Gain degeneration can be modulated in concert with the bias current modulation to stabilize amplifier gain.

A power amplifier circuit for broadband data communication over a path in a communication network can reduce or avoid gain compression, provide low distortion amplification performance, and can accommodate a wider input signal amplitude range. A dynamic variable bias current circuit can be coupled to a differential pair of transistors to provide a dynamic variable bias current thereto as a function of input signal amplitude. Bias current is increased when input signal amplitude exceeds a threshold voltage established by an offset or level-shifting circuit. The frequency response of the bias current circuit can track the full frequency content of the input signal, rather than its envelope. Gain degeneration can be modulated in concert with the bias current modulation to stabilize amplifier gain.

In accordance with aspects of the present invention, embodiments of a photodiode circuit. A photodiode circuit according to some embodiments includes a transimpedance amplifier; a resistor coupled across the transimpedance amplifier; and an amplifier stage coupled to receive an output from the transimpedance amplifier, wherein the photodiode circuit provides dynamic range across a current range of the photodiode circuit. In some embodiments, the transimpedance amplifier includes a receive signal strength indicator that provides a DC current signal to a tail of a first amplifier stage, the tail providing a current that is adaptively related to the DC current. In some embodiments, the resistor is a shielded resistor. In some embodiments, the adaptive current sink includes a plurality of switchable parallel current sinks.