The ADN2891 is high gain, 3.2Gb/s limiting amplifier optimized for use in SONET, Gigabit Ethernet (GbE), and Fibre Channel optical receivers that accept input levels of up to 2.0Vp-p differential and have 4mV p-p differential input sensitivity. The ADN2891 provides receiver functions of quantization and loss of signal (LOS) detection. The ADN2891 operates at up to 3.2Gb/s to support LX4 transceivers. The limiting amplifier also measures average received power based on a direct measurement of the photodiode current with better than 1dB of accuracy over the entire input range of the receiver. This eliminates the need for external average Rx power detection circuitry in SFF-8472 compliant optical transceivers. The ADN2891 limiting amplifier operates from a single 3.3V supply, has low power dissipation, and is available in a space saving 3 mm x 3 mm 16-lead lead frame chip scale package (LFCSP).