AMPLIFIER AND OPTICAL MODULE PERFORMING GAIN CONTROL

摘要

An amplifier includes a first transistor having a first conducting electrode receiving a current, a control electrode coupled to the first conducting electrode, and a second conducting electrode coupled to a fixed voltage source; a second transistor having a first conducting electrode, a second conducting electrode and a control electrode coupled to the control electrode of the first transistor; a feedback resistance coupled to the control electrode of the second transistor for feeding back an output of the second transistor to the control electrode of the second transistor; and a variable resistance element for controlling a ratio between a current flowing from the first conducting electrode of the first transistor into the control electrode of the second transistor and the feedback resistance and a current flowing from the first conducting electrode into the second conducting electrode in the first transistor.