Mixed-signal techniques in mm-wave range for 100 Gbit decision feedback equalizer

The design of very high speed broadband latched comparators and D flip-flops in 0.13 ¿m SiGe bipolar technology is presented. The latched comparators are used as a broadband front-end of a 1-tap decision feedback equalizer (DFE) for 100 Gb/s optical communication. Techniques for evaluating the bandwidth of the differential voltage gain from the single ended S-parameter measurements of the designed comparators up to 110 GHz are presented. The measurement results show a 3 dB bandwidth of about 70.5 GHz for the differential voltage gain. A static frequency divider is also fabricated to evaluate the performance of the designed D flip-flops used in the DFE in time domain and operates in measurement up to 86 GHz while consuming power as low as 96.25 mW per latch. A half rate parallel look-ahead architecture is used for the implementation of the DFE.