ADN2892:  3.3 V 4.25 Gb/s Limiting Amplifier

The ADN2892 is a high gain, limiting amplifier optimized for use in Fibre Channel and GbE optical receivers. The ADN2892 accepts input levels of up to 2.0 V p-p differential and has 3 mV p-p differential input sensitivity. The ADN2892 provides the receiver functions of quantization and loss of signal (LOS) detection.

The ADN2892 has an on-chip selectable filter to reduce the BW of the limamp to 1.5GHz in order to filter out the relaxation oscillation of legacy 1Gb/s Fiber Channel transmitters with CD lasers. The reduced BW will also allow for more optical Rx sensitivity margin at the lower data rates such as 1xFC and 1GbE in multi-rate modules.

The limiting amplifier also measures average received power based on a direct measurement of the photodiode current with better than 1 dB 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 ADN2892 limiting amplifier operates from a single 3.3 V supply, has low power dissipation, and is available in a spacesaving 3 x 3 mm 16-lead lead frame chip scale package (LFCSP).

Applications