Hitachi ULTRASTAR 15K450 HUS154530VLF400 - Manual (Page 48)

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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9.2 Ripple Voltage
Table 20: Power Supply Generated Ripple at Drive Power Connector
During drive start up and seek, 12 volt ripple is generated by the drive (referred to as dynamic loading). If the power of several
drives is daisy chained, the power supply ripple plus other drive dynamic loading must remain within the regulation tolerance
of +5%. A common supply with separate power leads to each drive is a more desirable method of power distribution.
To prevent external electrical noise from interfering with the drive's performance, the drive must be held by four screws in a
user system frame that has no electrical level difference at the four screw positions. The drive enclosure must not be used in
the current return path of the drive power supply. The maximum common-mode noise current passing through the drive must
not exceed 20 mA.
9.3 Power Consumption Efficiency Index
Table 21: Power Consumption Efficiency Index
Maximum (mV pp) MHz
+5 V DC 250 0-10
+12 V DC 250 0-10
Model 450GB Model 300 GB Model
Power Consumption Efficiency Index -Idle Mode (W/GB) 0.028 0.042