Optical receiver pre-amplifier which prevents ringing by shunting an input current of the pre-amplifier

摘要

An inverting amplification circuit and a feedback resistor are connected in parallel with each other between an input terminal and an output terminal, so that an input current flowing from a photodiode can be converted into an output voltage. Furthermore, a shunt transistor is disposed with its source connected with the input terminal, its gate connected with the output terminal and its drain connected with a ground power supply. When the input current is large, a current flowing into the feedback resistor is decreased, so that a part of the input current can be shunted by the shunt transistor in accordance with a voltage difference between the input terminal and the output terminal. Thus, the output voltage waveform can be free from ringing.