Application Design Center - Desktop / Notebook

Circuit Protection of Hard Disk Drive

Solutions

• 435
• 438
• 467
• ML
• SMAJ

Design Notes:

Protection Application:

For internal hard disk drives, the drive resides within the chassis of the application. This precludes the user from contacting the data bus, so ESD is not expected to be a threat. On the power bus (typically 3.3VDC to 12VDC), the threats will be surge transients, ESD and overload currents.

Solution Description:

As shown at the left, an SMD chip fuse can be used for overload current protection, and a TVS diode or MLV for surge transients and ESD protection. The specific part numbers are determined by matching the power bus operating voltage to that of the suppressor.

Companion Solutions:

Does not apply.

Regulatory Issues:

The IEC 61000-4-2 will be the most appropriate standard that applies for this port. It supplies a test method for verifying that the end product is not susceptible to ESD events.

Unique Features:

Does not apply.

Application Warnings:

Does not apply.