A loss of signal circuit has a multiplexer and a photodiode coupled to a first input of the multiplexer. A reference signal generator is coupled to a second input of the multiplexer. An amplifier is coupled to an output of the multiplexer. A demultiplexer includes an input of the demultiplexer coupled to an output of the amplifier. A first capacitor is coupled to a first output of the demultiplexer. A second capacitor is coupled to a second output of the demultiplexer. A comparator has a first input coupled to the first output of the demultiplexer and a second input of the comparator is coupled to the second output of the demultiplexer.