A 1-mW 12-Gb/s continuous-time adaptive passive equalizer in 90-nm CMOS

This paper presents a frequency-domain adaptive passive equalizer for high-speed receivers. A local control loop, without feedback from the final receiver output, is used to automatically adjust the gain compensation for different channel characteristics. As a result, the equalizer does not rely on the recovered clock signal. Implemented in a 90-nm digital CMOS process, the equalizer can provide up to 13 dB of gain compensation with 6 dB of tuning range while consuming 1 mW from a 1-V supply. The equalizer is able to open the data eye of a 12-Gb/s PRBS signal after a 72-inch RG-58 coaxial cable and an 8-inch FR-4 trace, whose attenuations at 6 GHz are 10.8 and 13 dB, respectively.