MAX3949ETE+T

The MAX3949 is a 3.3V, multirate, low-power laser diode driver designed for Ethernet, Fibre Channel, and SONET transmission systems at data rates up to 11.3Gbps. This device is optimized to drive a differential transmit­ ter optical subassembly (TOSA) with a 25Ω flex circuit. The unique design of the output stage enables use of unmatched TOSAs.

The device receives differential AC-coupled signals with on-chip termination. It can deliver laser modulation cur­ rents of up to 85mA at an edge speed of 22ps (20% to 80%) into a 5Ω external differential load. The device is designed to have a high-bandwidth differential signal path with on-chip back termination resistors integrated into its outputs. An input equalization block can be activated to compensate for SFP+ host connector losses. The inte­ grated bias circuit provides programmable laser bias cur­ rents up to 105mA. Both the laser bias current generator and the laser modulator can be disabled from a single pin.

The use of a 3-wire digital interface reduces the pin count while permitting adjustment of input equalization, polar­ ity, output deemphasis, and modulation and bias currents without the need for external components. The device is available in a 3mm × 3mm, 16-pin TQFN package, and is specified for the -40°C to +95°C extended temperature range.