The MAX3861 is a low-power amplifier with automatic gain control (AGC), designed for WDM transmission systems employing optical amplifiers and requiring a vertical threshold adjustment after the post amp. Operating from a single 3.3V supply, this AGC amplifier linearly amplifies/attenuates the input signal while maintaining a fixed output-voltage swing at data rates up to 2.7Gbps. The input and output are on-chip terminated to match 50 interfaces.