A 200 MSample/s trellis-coded PRML read/write channel with digital servo

A fully-integrated R/W IC operates at 200 MSample/s channel rate and supports two recording codes: a rate 4/5 (0,4/8) matched spectral null (MSN) trellis code and associated detector, and a rate 8/9 (0,4/4) with a standard maximum-likelihood PR4 detector. The chip supports a complete flexible digital servo and four-level write precompensation to overcome media nonlinearity. The device is integrated in 0.7 /spl mu/m BiCMOS technology, has 54 mm/sup 2/ die and uses 2 W with MSN code or 1.5 W with PR4 code at 4.5 V and 200 MSample/s. This chip avoids external interface chips, incorporating an ADC and functions useful to the servo DSP. MSN code provides approximately 2 dB gain in SNR with respect to rate 8/9 PR4 coding at a user density of PW/sub 50//T/sub max/=1.8.