Magnetic recording disk drive with write driver to write head transmission line having non-uniform sections for optimal write current pulse overshoot

Abstract

An interconnect between the write driver and the write head in a magnetic recording disk drive enables an inherent write current overshoot. The interconnect includes an integrated lead suspension (ILS) and a short flex cable that connects the write driver circuitry to the ILS. The interconnect is a two-segment transmission line, with the first segment connected to the write driver having multiple sub-segments or sections with non-uniform impedance levels. The section of the first segment that connects to the write driver is the short flex cable and has an impedance substantially higher than the source impedance Zof the write driver. The multiple sections of the first segment have non-uniform impedance values that have an effective impedance Zthat substantially matches Z. The second segment of the transmission line has an effective impedance Zthat is substantially less than Z. The write lines for the +W and −W signals are preferably interleaved on the transmission line sections.