A Methodology to Identify Crosstalk Contributor from 6-Line Suspension Assembly Interconnect of Ultra-High Capacity Hard Disk Drives

摘要

The crosstalk phenomenon on the suspension assembly interconnecting trace (SAIT) in hard disk drives (HDD) causes the signal to deform and/or degrade the recording head. For the purpose of analyzing the crosstalk contributions from SAIT using the 3D electromagnetic simulation tool, SAIT is divided into 4 sections which are bend section (BS), far-end section (FS), straight section (SS), and near-end section (NS). The length of each section is selected based on the physical shape of the trace and characteristic impedance. From the results, it was observed that the lowest crosstalk occurs at the BS and the highest crosstalk occurs at the NS. NS is necessary during a HDD quality evaluation and is removed before the SAIT installed in the HDD. With such high crosstalk, the test results can indicate poor head performance even when the head is working properly. Moreover, the crosstalk can be suppressed up to 14 dB and 33 dB for the near-end side and the far-end side, respectively when the NS with a 100% filled stainless steel backing layer is applied to the SAIT. Hence, to improve the accuracy of the recording head test performance, the designer should put more effort to design the SAIT near-end section to minimize crosstalk.