Decision-Feedback-Equalizer for 10-Gb/s backplane transceivers for highly lossy 56-inch channels

This paper presents a decision-feedback-equalizer for 10-Gb/s backplane transceivers for highly lossy channels. Forward equalization is not used in order to avoid noise enhancement. The sampling phase is optimized to achieve maximum signal-to-noise-ratio at the sampling instants. The coefficients of feedback finite-impulse-response filter and the gain of variable-gain-amplifier are obtained automatically by adaptive circuits. The vertical eye opening is almost doubled compared with a conventional decision-feedback-equalizer for a 56-inch channel with heavy loss more than -6.5 dB/GHz. The DFE is implemented in 0.13-mum IBM RF CMOS technologies. Results show an 8-tap DFE can open the highly blurred eye diagram, while a 12-tap conventional DFE can not open it. A 10-tap DFE yields a very clear eye diagram for PRBS-9 test patterns.