Transimpedance Amp Targets Fiber Optic Receivers

The ADN2820 transimpedance amplifier (TIA) is optimized for OC-192 and 10 Gigabit Ethernet (GbE) fiber optic links in metro area access applications. Although it can be used in any optical module, the new TIA is targeted at short- and intermediate-reach links. It offers high gain, low input noise and can directly drive a clock-and-data-recovery (CDR) IC or transceiver, eliminating the need for an external post-amplifier in most short-reach/intermediate-reach optical modules for SONET/SDH OC-192 and 10 GbE. A 5,000_ transimpedance coupled with 1.1 µA input noise current provide the same level of optical sensitivity as designs using standard TIAs, but without a post-amplifier and its contributed noise. Other features of the TIA includes an analog power monitor to enable loss-of-power alarms and an analog signal detect for supporting loss-of-signal alarms and simplifying fiber alignment during assembly. The device runs from a 3.3V supply and consumes 250 mW (typ.). Price: $90 each/1,000. ANALOG DEVICES INC., Wilmington, MA. (781) 937-1428.