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 50Ω interfaces. This amplifier has a small-signal bandwidth of 3.4GHz and an input-referred noise of 0.26mVRMS. Over an input signal range of 6mVP-P to 1200mVP-P (46dB), the MAX3861 delivers a constant output amplitude adjustable from 400mVP-P to 920mVP-P. Variation in output swing is controlled within 0.2dB over a 16dB input range. The MAX3861 provides a received-signalstrength indicator (RSSI) that is linear, within 2.5%, for input signal levels up to 100mVP-P and an input signal detect (SD) with programmable threshold. Applications * Continuous Rate Receivers * Long-Reach Optical Receivers * OC-48/STM-16 Transmission Systems * WDM Optical Receivers