A 2.5-V, 40-Gb/s decision circuit using SiGe BiCMOS logic

A 40-Gb/s decision circuit is reported which operates from a 2.5-V supply. It includes a flip-flop, a broadband transimpeclance preamplifier, a tuned 40-GHz clock buffer, and a 50-/spl Omega/ output driver. The flipflop features a novel BiCMOS CML logic topology, which allows for lower supply voltages as compared with pure bipolar implementations without compromising speed. A mm-wave transformer is used to perform single-ended-to-differential conversion along the 40 GHz clock path.