Semtech Corporation
Automatic Gain Control for Passive Optical Network

Abstract:

An automatic gain control circuit controls a gain of a burst mode amplifier. A peak detector includes an input coupled to an output of the amplifier. A plurality of resistors is coupled in series between an input of the first amplifier and the output of the first amplifier for setting the gain of the amplifier. A first gain stage is responsive to an output signal of the peak detector for disabling a first resistor of the plurality of resistors to alter the gain of the first amplifier. A second gain stage is responsive to the output signal of the peak detector for disabling a second resistor of the plurality of resistors to alter the gain of the first amplifier. A comparator responsive to the output signal of the peak detector causes a pulse generator to enable the first gain stage and second gain stage each burst mode.