The DS1878 controls and monitors all functions for SFF, SFP, and SFP+ optical modules and fully supports the SFF-8472 standard. It can be combined with a MAX3798 or MAX3799 SFP+ laser driver/limiting amplifier to provide an automatic power control (APC) loop, modulation current control, and eye safety functionality—the core feature set of SFP and SFP+ optical modules. The DS1878 also works with the MAX3945 limiting amplifier or the MAX3946 LDD to support 10GHz applications featuring distributed feedback (DFB) or electro-absorption-modulated (EML) lasers.
Laser modulation is controlled with a dedicated temperature-driven lookup table (LUT). Two additional 9-bit delta-sigma DAC outputs with 36-entry LUTs are provided. The DS1878 monitors six analog channels: temperature, Vcc, and MON1 to MON4; MON3 is a fully differential input.
The DS1878 is specified over the -40 degrees Celsius to +95 degrees Celsius temperature range. It uses 0.35micrometer technology to enable the high level of integration required for SFF-8472 implementation in a small 5mm x 5mm, 28-pin TQFN package with exposed pad. Pricing begins at $1.33 (1000-up, FOB USA).
