A 125-MHz mixed-signal echo canceller for Gigabit Ethernet on copper wire

A discrete-time analog echo canceller is described that reduces the echo in the front end of Gigabit Ethernet twisted-pair interfaces. Echo cancellation in the analog domain by means of four taps reduces the complexity of the digital echo canceller and crosstalk cancellers. Designed in a 0.4-/spl mu/m CMOS technology, the circuit employs an LMS algorithm to adapt to the cable length and impedance discontinuities, providing an echo suppression of 10 dB. The design operates at 125 MHz while consuming 43 mW from a 3-V supply.

[1]  K. Azadet,et al.  A low power 128-tap digital adaptive equalizer for broadband modems , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[2]  B. Razavi,et al.  An 8-bit 150-MHz CMOS A/D converter , 1999, IEEE Journal of Solid-State Circuits.

[3]  Marcel J. M. Pelgrom,et al.  Transistor matching in analog CMOS applications , 1998, International Electron Devices Meeting 1998. Technical Digest (Cat. No.98CH36217).

[4]  Francois Krummenacher,et al.  A 4-MHz CMOS Continuous-Time Filter with On-Chip Automatic Tuning , 1987, ESSCIRC '87: 13th European Solid-State Circuits Conference.