Seagate ST118202LC, Руководство по эксплуатации продукта

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Cheetah 18 Product Manual, Rev. B 19
6.0 Physical/electrical specifications
This section provides information relating to the physical and electrical characteristics of the Cheetah 18 drive.
6.1 AC power requirements
None.
6.2 DC power requirements
The voltage and current requirements for a single drive are shown in the following table. Values indicated apply
at the drive power connector. The table shows current values in Amperes.
Table 2: DC power requirements
[1] Measured with average reading DC ammeter. Instant12 V current peaks will exceed these val-
ues.
[2] For +12 V, a –10% tolerance is permissible during initial start of spindle, and must return to ±5% before
10,000 rpm is reached. 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 +12 V current profile in Figure 3.
[4] This condition occurs when the Motor Start Option is enabled and the drive has not yet received a Start
Motor command.
[5] See Section 6.2.1 “Conducted Noise Immunity.” Specified voltage tolerance is inclusive of ripple, noise,
and transient response.
[6] At power up, the motor current regulator limits the 12 volt current to an average of less than 2.1 amperes,
although instantaneous peaks may exceed this value. These peaks should measure 5 msec duration or
less.
[7] Operating condition is defined as a third stroke seek at OD and read one track. Command issued every
0.042 seconds.
[8] No terminator power.
[9] During idle, the drive heads are relocated every 60 seconds to a random location within the band from
track zero to one-fourth of the maximum track. This results in a random variation in +12 volt idle current of
0.0152 amperes (0.182 watts).
General Notes from Table 2:
1. Minimum current loading for each supply voltage is not less than 2% of the maximum operating current
shown.
2. The +5 and +12 volt supplies shall 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 start-
ing current must be available to each device.
4. Parameters, other than spindle start, are measured after a 10-minute warm up.
Notes SE mode LVD mode
Voltage +5 V +12 V +5 V [8] +12 V
Regulation [5] ±5% ±5%[2] ±5% ±5% [2]
Maximum operating current DC3
σ
[1] 0.88 1.22 0.95 1.22
Average idle current DCX [1][9] 0.72 0.98 0.74 0.98
Maximum starting current
(peak DC) DC3
σ
(peak AC) AC3
σ
[3] [6]
[3] 0.89 2.5
3.2 0.90 2.5
3.2
Delayed motor start (max) DC3
σ
[1][4] 0.66 0.03 0.68 0.03
Peak operating current
Typical DCX
Maximum DC3
σ
Peak (avg) DC3
σ
[1][7]
[1] 0.85
0.88
1.07 1.2
1.22
2.6 0.93
0.95
1.3 1.2
1.22
2.6