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USER RESPONSIBLE FOR VERIFYING VERSION AND COMPLETENESS
OEM FUNCTIONAL SPECIFICATION ULTRASTAR XP (DFHC) SSA MODELS 1.12/2.25 GB - 1.0" HIGH
2.2.5 Power Supply Ripple
Externally Generated Ripple
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as seen at drive power connector Maximum Notes
+5VDC 150 mV 0-20 MHz
peak-to-peak
+12VDC 150 mV 0-20 MHz
peak-to-peak
During drive start up and seeking, 12 volt ripple is generated by the drive (referred to as dynamic loading). If
several drives have their power daisy chained together then the power supply ripple plus other drive's
dynamic loading must remain within the regulation tolerance window of + / - 5%. A common supply with
separate power leads to each drive is a more desirable method of power distribution.
2.2.6 Grounding Requirements of the Disk Enclosure
The disk enclosure is at Power Supply ground potential. It is allowable for the user mounting scheme to
common the Disk Enclosure to Frame Ground potential or to leave it isolated from Frame Ground.
From a Electro-Magnetic Compatibility (EMC) standpoint it will, in most cases be preferable to common
the Disk Enclosure to the system's mounting frame. With this in mind, it is important that the Disk Enclo-
sure not become an excessive return current path from the system frame to power supply. The drive's
mounting frame must be within ± 150 millivolts of the drive's power supply ground. At no time should
more than 35 milliamps of current (0 to 100Mhz) be injected into the disk enclosure.
Please contact your IBM Customer Representative if you have questions on how to integrate this drive in
your system.
2.2.7 Hot plug/unplug support
Power supply and SSA link hot plug and un-plug is allowed for all SSA models.
For Form Factor models, there is no special sequence required for connecting 5 volt, 12 volt, or ground.
During a hot plug-in event the drive being plugged will draw a large amount of current at the instant of
plug-in. This current spike is due to charging the bypass capacitors on the drive. This current pulse may
cause the power supply to go out of regulation. If this supply is shared by other drives then a low voltage
power on reset may be initiated on those drives. Therefore the recommendation for hot plugging is to have
one supply for each drive. Never daisy chain the power leads if hot plugging is planned. Hot plugging
should be minimized to prevent wear on the power connector.
The carrier models may be hot plugged ONLY IF the ground pins (longer pin) make contact first (before
other pins which are shorter). Vice versa, the carrier may be hot unplugged ONLY IF the ground pins
(longer pins) are the last to remove (after other pins which are shorter). DAMAGE TO THE FILE ELEC-
TRONICS AND THE ADAPTER ELECTRONICS COULD RESULT IF THE ABOVE CONDITIONS
ARE NOT MET. The mating HPC connector MUST HAVE PROGRAMMABLE PIN LENGTH. GND
PINS MUST BE LONGER THAN SIGNAL AND POWER PINS. THE GUIDE PINS MUST BE TIED
TO THE DOKING ASSEMBLY FRAME GND
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This ripple must not cause the power supply to the drive to go outside of the ± 5% regulation tolerance.
Source filename=POWERIBM CorporationPage 34 of 87