A 50 MHz, standard CMOS, pulse equalizer for hard disk read channels

A pulse equalizer for hard disk systems is presented. Opposed to classical realizations it is full CMOS while operating at 50 MHz cut-off frequency. For pulse slimming, the equalizer is capable of 13 dB selective boost around the cut-off frequency. The equalizer is a gm-C, seventh order 0.05° equiripple-on-the-phase low pass filter. It is made out of highly symmetrical biquads with elementary OTAs. The inaccuracies are compensated with a in this work introduced tuning system. This guarantees a ripple on the group delay of 2%. The results are confirmed on silicon.