A CMOS 3.5 Gbps continuous-time adaptive cable equalizer with joint adaptation method of low-frequency gain and high-frequency boosting

Abstract

This paper describes a high-speed CMOS adaptive cable equalizer with the joint adaptation method of low-frequency gain and high-frequency boosting. The adaptation method compares not only the high-frequency contents but also the low-frequency contents. By this joint adaptation method, the adaptation inaccuracy due to amplitude deviation can be reduced. The filter cell in the equalizer uses the variable-capacitor tuning and feed-forward common-mode-voltage biasing technique to achieve high bandwidth. The prototype chip is fabricated in a 0.18 /spl mu/m mixed-mode CMOS process. The realized active area is 0.48 mm/spl times/0.73 mm. The filter cell operates up to 5 Gbps and the adaptive equalizer operates up to 3.5 Gbps over a 15-m RG-58 coaxial cable with a 1.8 V supply and 80 mW power dissipation.