ADI laser diode drivers enable dual-loop capability for 3.3V apps

The ADN2847 and ADN2848 laser diode drivers extend dual-loop capability to 3.3V applications. These "anyrate" drivers support data rates from 50Mbps to 3.3Gbps. These devices allow the use of less-expensive optics since they compensate for variations that occur in laser diodes over time and temperature changes.

Operating at reduced supply voltages, the chips enable consistent optical performance over a wide range of temperatures and operating conditions in applications such as SONET OC-3/12/48, SDH STM-1/4/16, Fibre Channel and Gigabit Ethernet modules.

They actively manage laser diode output power by continuously sensing the transmitted optical signal and correcting it for variations caused by laser diode degradation or changes in operating temperature. This feature is especially important in uncooled applications, and those that require long-term stability and reliability. This dual-loop architecture enables the drivers to work with any standard monitor photodiode, while avoiding any data format limitations.

Together, the devices also provide flexibility and are pin-to-pin compatible. The ADN2848 targets 50Mbps to 622Mbps applications, while the ADN2847 supports data rates from 50Mbps up to 3.3Gbps. Both operate from a single 3V to 3.6V supply. The drivers feature modulation currents up to 80mA and bias currents up to 100mA. Additional features include laser fail and degrade alarms, automatic laser shutdown, bias current monitors and modulation current monitors.

The ADN2847 laser diode driver is offered in both 7-by-7mm 48-lead and 5-by-5mm 32-lead CSPs, while the ADN2848 comes in a 5-by-5mm 32-lead CSP. Pricing is at $23 and $11.25, respectively, in 1,000-piece quantities.