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[1]
Measured with an oscilloscope & current probes at 20 megasamples/second (50ns/point). Power supply at nominal voltage.
N (number of drives tested) = 12, 35
[2]
For +12 V, a –10% tolerance is allowed during initial spindle start but must return to ± 5% before reaching 7200 RPM.
The ± 5% must be maintained after the drive signifies that its power-up sequence has been completed and
that the drive is able to accept selection by the host initiator.
[3]
See +12V current profile in
[4]
This condition occurs after OOB and Speed Negotiation completes but before the drive has received the Notify Spinup primitive.
[5]
See
6.4.1, "Conducted noise immunity."
[6]
During idle, the drive heads are relocated every 60 seconds to a random location within the band from three-quarters to maximum track.
[7]
Power Balance allows the user to lower drive power at a performance loss (approximately 6% random, 50% sequential).
See
Section 6.2, "Power Balance"
[8]
"Typical DCX" is an average current value of all drives tested, i.e. avg(I
[9]
"Maximum DC" is the maximum average operating current of all drives tested, i.e. max(I
Note that the maximum DC 5V current value & maximum DC 12V current value are from different drives.
[10] "Maximum (peak) DC" is the maximum single point (>=50ns in duration) recorded by the oscilloscope on any of the drives tested,
i.e. max(I
, I
maxpoint,drive1
General DC power requirement notes.
1.
Minimum current loading for each supply voltage is not less than 1.7% of the maximum operating current shown.
2.
The +5V and +12V supplies should employ separate ground returns.
3.
Where power is provided to multiple drives from a common supply, careful consideration for individual drive power requirements should be
noted. Where multiple units are powered on simultaneously, the peak starting current must be available to each device.
4.
Parameters, other than spindle start, are measured after a 10-minute warm up.
5.
Idle power after power-on will be higher than indicated until the drive has verified the media. Idle power will then return to the indicated
values.
6.
Drive hardware limits +5V current draw to approximately 1.4A
6.4.1
Conducted noise immunity
Noise is specified as a periodic and random distribution of frequencies covering a band from DC to 10 MHz. Maximum allowed noise values given
below are peak-to-peak measurements and apply at the drive power connector.
+5v
=
250 mV pp from 100 Hz to 20 MHz.
+12v
=
250 mV pp from 100 Hz to 5 MHz.
6.4.2
Power sequencing
The drive does not require power sequencing. The drive protects against inadvertent writing during power-up and down.
Seagate Exos 2X14 SAS Product Manual, Rev. D
o
C ambient.
Figure
1. (for 14TB models)
Specified voltage tolerance includes ripple, noise, and transient response.
for details on how to enable Power Balance.
,... I
maxpoint,drive2
maxpoint,driveN
, I
avg,drive1
avg,drive2
).
.
avg
Physical/electrical specifications
,... I
).
avg,driveN
, I
,... I
avg,drive1
avg,drive2
avg,driveN
).
23
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