An 80 Mb/s adaptive DFE detector in 1 /spl mu/m CMOS [hard-disk drives]

This paper describes a continuous-time forward equalizer (CTFE) with one adaptive right-half-plane zero that removes the precursor ISI and an adaptive RAM DFE that removes the postcursor ISI. Because the DFE cancels post-cursor ISI noiselessly, the post-cursor ISI cancellation does not degrade the signal-to-noise ratio. The prototype also includes a 7th-order linear-phase low-pass ladder filter to provide anti-aliasing and to suppress channel noise. The key contribution here is the implementation of this adaptive one-zero forward equalizer in conjunction with the low-pass filter and adaptive mixed-signal RAMDFE on the same IC. Because two continuous-time outputs from the low-pass filter are combined to build the core of the adaptive forward equalizer, it is constructed with little hardware beyond that already required for the low-pass filter.