Seagate ST318405LW/LC ユーザーズマニュアル
Cheetah 36XL Product Manual, Rev. E
23
6.0
Physical/electrical specifications
This section provides information relating to the physical and electrical characteristics of the Cheetah 36XL
drive.
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.
at the drive power connector. The table shows current values in Amperes.
Table 2:
DC power requirements
Notes.
[1]
Measured with average reading DC ammeter or equivalent sampling scope. Instantaneous current peaks
will exceed these values. Power supply at nominal voltage. N = 2, 22 Degrees C ambient.
will exceed these values. Power supply at nominal voltage. N = 2, 22 Degrees C ambient.
[2]
For +12 V, a –10% tolerance is permissible during initial start of spindle, and must return to ±5% before
10,017 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.
10,017 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.
Motor command.
[5]
See Section 6.2.1 “Conducted Noise Immunity.” Specified voltage tolerance is inclusive of ripple, noise,
and transient response.
and transient response.
[6]
Operating condition is defined as random 8 block reads at 151 I/Os per second. Current and power speci-
fied at nominal voltages. Decreasing +5 volts by +5% increases +5 volt current by 4.7%.
fied at nominal voltages. Decreasing +5 volts by +5% increases +5 volt current by 4.7%.
[7]
During idle, the drive heads are relocated every 60 seconds to a random location within the band from
track zero to one-fourth of maximum track.
track zero to one-fourth of maximum track.
General Notes from Table 2:
1.
Minimum current loading for each supply voltage is not less than 1.2% of the maximum operating current
shown.
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.
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.
5.
No terminator power.
Notes
ST336705
ST318405
ST39205
Voltage
+5 V
+12 V
+5 V
+12 V
+5 V
+12 V
Regulation
±5%
±5%[2]
±5%
±5%[2]
±5%
±5%[2]
Average idle current DCX
0.71
0.50
0.71
0.37
0.76
0.32
Maximum starting current
(peak DC) DC
1.00
2.30
1.00
2.30
1.00
2.30
Delayed motor start (max) DC
0.58
0.03
0.57
0.03
0.80
0.08
Peak operating current
DCX
Maximum DC
Maximum (peak)
Maximum DC
Maximum (peak)
0.81
0.84
1.65
0.84
1.65
0.75
0.81
2.23
0.81
2.23
0.78
0.82
1.56
0.82
1.56
0.60
0.69
1.89
0.69
1.89
0.90
0.94
1.78
0.94
1.78
0.56
0.90
1.91
0.90
1.91