A 6-Bit, 12.5 GS/s Comparator for High-Speed A/D Conversion in 0.35 μM SiGe BiCMOS Technology

This paper presents a monolithic comparator implemented in CHRT 0.35 mu m SiGe BiCMOS technology for high-speed medium-resolution flash analog-to-digital conversion. The SiGe BiCMOS process provides HBT transistors with maximum f(T) as 55 GHz. The comparator occupies a die area of 240x65 mu m(2) with a power dissipation of 54.16 mW from a 3.3-V power supply. Operating with an input frequency of I GHz, the circuit can oversample up to 12.5 GS/s with 7 bits of resolution; while operating at Nyquist, the comparator can sample up to 12.5 GS/s with 6 bits resolution. This design achieves a considerable trade-off between power, speed and resolution.