Title :
Designing disk drive interconnects to obtain a desired transmitted write current waveform
Author :
Jury, Jason C. ; Batra, Sharat ; Wang, X.
Author_Institution :
Dept. of Electr. Eng., Stanford Univ., CA, USA
Abstract :
This paper describes the application of nonuniform transmission lines as interconnects for disk drive applications. The design method that we use is a direct optimization, approximating the interconnect as a cascade of piecewise uniform transmission line segments. Models for the write head, interconnect, and write driver are provided. We find nonuniform interconnects are most effective for low-turn heads (<5 turns). We explore nonuniform interconnects as a way of inducing write current overshoot with short settling times (i.e., minimal ringing). For interconnects with total (one-way) propagation delay td, the effective overshoot duration ranges from 2td to 100 ps. The effective overshoot amplitude is <50%. The waveforms generated by nonuniform interconnects are limited primarily by the constraint on the interconnect length. Any additional mechanical constraints on specific regions of the interconnect may cause the design impedance profile to be compromised. If this is the case, multiple smaller constrained regions are preferred to a single large region.
Keywords :
disc drives; interconnections; optimisation; pulse shaping; transmission line theory; design method; direct optimization; disk drive interconnect design; disk drive suspension interconnect; low-turn heads; mechanical constraints; nonuniform interconnects; nonuniform transmission lines; piecewise uniform transmission line segments; pulse shaping; short settling times; transmitted write current waveform; write current overshoot; write driver model; write head model; Design methodology; Design optimization; Disk drives; Distributed parameter circuits; Impedance; Integrated circuit interconnections; Magnetic heads; Propagation delay; Pulse shaping methods; Reflection;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2002.988911