The part is a high performance BICMOS read channel IC that provides all of the functions needed to implement an entire Partial Response Class 4 (PR4) read channel for zoned recording hard disk drive systems with data rates from 67 to 212 Mbps. Functional blocks include a serial port, an automatic gain control amplifier, a programmable filter, an offset canceller, a peak detecting pulse qualifier, an adaptive transversal filter, a Viterbi qualifier, a 8/9 GCR ENDEC, a data synchronizer, a time base generator, an integrating servo demodulator, as shown in figure 1.