Transimpedance Amplifier with Bandwidth Extender

摘要

A transimpedance amplifier that includes an input configured to receive a current input from an upstream device and output configured to present an output voltage. The current input may be from a photodetector or any other device that is part of an optical signal receiving unit front end. In one configuration, there are three amplifier stages in the transimpedance amplifier connected in series. A feedback path with feedback resistor connects between the input and output of the transimpedance amplifier. A bandwidth extender circuit connects between a stage output and a stage input of the transimpedance amplifier. In a three stage embodiment, the bandwidth extender circuit extends between an input of the second stage and the output of the second stage. The bandwidth extender includes at least one active device configured to provide positive feedback to increase gain. The bandwidth extender circuit is able to be automatically or selectively deactivated to filter unwanted frequency components.

主权项

1. An photodetector with a transimpedance amplifier comprising:
a photodetector configured to receive and process an optical signal to generate a photodetector output that represents the optical signal a transimpedance amplifier having a transimpedance amplifier input and a transimpedance amplifier output, the transimpedance amplifier input configured to receive the photodetector output, the transimpedance amplifier including a first stage comprising a transistor and a load element, the first stage connected to the photodetector output and having a first stage output; a second stage comprising a transistor and a load element, the second stage connected to the first stage output and having a second stage output; a third stage comprising a transistor and a load element, the third stage connected to the second stage output and forming the transimpedance amplifier output; a first feedback loop including feedback resistor, the feedback loop connected between to the transimpedance amplifier output and the transimpedance amplifier input; a bandwidth extender including an active element, a bandwidth extender connected between the first stage output and the second stage output.