A 1.2Gb/s write driver with pre-emphasis overshoot control optimized for high density HDD applications

This paper presents circuit techniques of a write driver with pre-emphasis control used as part of preamplifiers for hard disk drives (HDD). Fabricated in 0.35 mum SOI-BiCMOS process, it has demonstrated 1.2Gb/s data rate with write current amplitude over 180 mApp. Wide controllability of overshoot current is achieved in both amplitude and duration independently, suitable for not only longitudinal but perpendicular recording for high density HDD