A 7-bit, 18 GHz SiGe HBT comparator for medium resolution A/D conversion

An ultra-high-speed, master-slave comparator using an ECL configuration is presented. Implemented in a commercially-available 0.18 /spl mu/m 120 GHz SiGe HBT BiCMOS technology, the comparator core occupies a compact area of only 140 /spl times/ 325 /spl mu/m/sup 2/. Operating off a 3.5 V power supply, the comparator consumes 82 mW, excluding clock and output buffers. The comparator can operate at an 18 GHz sampling rate with 7.1 bits of resolution, and at a 20 GHz sampling rate with 4.9 bits of resolution. To our knowledge, this comparator achieves the highest resolution when compared to other stand-alone comparators in the literature operating at similar sampling rates.