A 1.5V 20/30 Gb/s CMOS backplane driver with digital pre-emphasis

A high-speed input comparator and output driver with adjustable pre-emphasis for applications in serial interchip communications over backplanes at 20 Gb/s is presented. The circuit was implemented in 130-nm CMOS and consumes 140 mW from a 1.5-V supply. It has over 30 dB dynamic range with a sensitivity of 20 mVp-p and a differential output swing of 700 mVp-p at 20 Gb/s. The output driver features a novel digital pre-emphasis circuit with independent pulse height and width control. Other features include 30%-70% eye-crossing control and adjustable output swing between 170 mVp-p and 350 mVp-p per side at data rates up to 30 Gb/s.