MAX3799应用电路(集成的低功耗SFP+多速率限幅放大器和VCSEL驱动器)

Typical Application Circuit

The MAX3799 is a highly integrated limiting amplifier and VCSEL driver that operates up to 14Gbps, making it suitable for Ethernet and Fibre Channel applications. By providing a selectable data path with a noise-shaping filter, the MAX3799 enables a module with 10G optics to be fully compliant with both 1000BASE-SR and 10GBASE-SR specifications. Operating from a single +3.3V supply, this low-power integrated limiting amplifier and VCSEL driver IC enables a platform design for SFP MSA as well as for SFP+ MSA-based optical transceivers. The high-sensitivity limiting amplifier limits the differential input signal generated by a transimpedance amplifier into a CML-level differential output signal. The compact VCSEL driver provides a modulation and a bias current for a VCSEL diode. The optical average power is controlled by an average power control (APC) loop implemented by a controller that interfaces to the VCSEL driver through a 3-wire digital interface. All differential I/Os are optimally back-terminated for a 50Ω transmission line PCB design.

The use of a 3-wire digital interface reduces the pin count while enabling advanced Rx (rate selection, LOS threshold, LOS squelch, LOS polarity, CML output level, signal path polarity, deemphasis, and fast mode-select change time) and Tx settings (modulation current, bias current, polarity, and eye safety control) without the need for external components. The MAX3799 provides multiple current and voltage DACs to allow the use of low-cost controller ICs.

The MAX3799 is packaged in a lead-free, 5mm x 5mm, 32-pin TQFN package.