Writing at high data rates

The physical restrictions on the write signal path in a hard disk drive are such that, at high data rates, the write electronics typically need a large voltage supply and generates much heat. In addition, the electronics produce inadequate write current wave forms that adversely affect the magnetic patterns to be recorded. After a brief overview of what has been proposed to alleviate this problem, a solution is presented wherein a high inductance head (56 nH) can be driven up to 1 Gb/s. This is made possible by compensating the head inductance into (nearly pure) resistance and matching this resistance to the characteristic impedance (75 Omega) of the 5 cm long driver-to-head interconnect. This compensation/matching only requires small, lossy capacitors, which can be implemented in the head-processing phase onto the head wafers as an integral part of head processing. (C) 2003 American Institute of Physics.