9.3.3 Power supply generated ripple at drive power connector
0–10150+12
0–10100+5
Frequency range
(MHz)
Maximum
peak-to-peak ripple voltage
(mV p-p)
DC Volts
(V)
Figure 47. Power supply generated ripple at drive power connector
During drive start up and seeking a 12-Volt ripple is generated by the drive—this is referred to as
dynamic loading. If the power of several drives is daisy chained together, then the power supply ripple
plus the dynamic loading of the other drives must remain within the above regulation tolerance. 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 performance of the drive, the drive must be
held in position by four screws in a user's system frame. There must be no electrical level difference at
the four screw positions and less than ±300 millivolts peak-to-peak difference level must be maintained
between the drive cover and the ground of the drive power connector.
9.3.4
Start up current
Since each drive model has the identical spindle motor design, rush currents shorter than 10 us in
duration are ignored in the measurement of the start up current of each model. For this reason a single
start up current graph represents each of the respective models in this specification.
Figure 48. Typical current wave form of the 12 V line at drive start up—listed by drive model capacity
Deskstar 60 GXP Hard disk drive specification
49
Time
seconds
Current (Amp)
DERA004.prz
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