A 10-Gb/s Adaptive Look-Ahead Decision Feedback Equalizer With an Eye-Opening Monitor

We demonstrate a novel adaptive look-ahead decision feedback equalizer (LADFE) that uses the measured eye diagram for equalization adaptation and verification. The eye diagram is obtained with a new type of eye-opening monitor (EOM), which measures the magnitude of the received signals having different data patterns and, using this, estimates intersymbol interference and determines the amount of adaptation needed for the LADFE. A 10-Gb/s adaptive two-tap LADFE with an EOM is fabricated in 90-nm CMOS technology. The eye diagrams for equalized signals are successfully obtained, and adaptation of the LADFE is achieved for PCB channels up to 40 cm. The LADFE core occupies and consumes 11 mW at 1.2-V supply voltage.