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CHEETAH 15K.7 FC PRODUCT MANUAL, REV. E 21
[1] Measured with average reading DC ammeter. Instantaneous +12V current peaks will exceed these values. Power sup-
ply at nominal voltage. N (number of drives tested) = 6, 35 Degrees C ambient.
[2] For +12 V, a –10% tolerance is allowed during initial spindle start but must return to ±5% before reaching 15000 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 Figure 1.
[4] This condition occurs when the Motor Start option is enabled and the drive has not yet received a Start Motor command.
[5] See paragraph 6.2.1, "Conducted noise immunity." Specified voltage tolerance includes ripple, noise, and transient
response.
[6] Operating condition is defined as random 8 block reads at 375 I/Os per second for 600GB models and 380 I/Os per sec-
ond for 450GB and 300GB models. Current and power specified at nominal voltages.
[7] During idle, the drive heads are relocated every 60 seconds to a random location within the band from three-quarters to
maximum track.
General DC power requirement notes.
1. Minimum current loading for each supply voltage is not less than 1.2% 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. No terminator power.
6.2.1 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.
Table 4 ST3300657FC DC power requirements
2 Gbit 4 Gbit
Note
s
(Amps) (Amps) (Amps) (Amps)
Voltage +5V +12V [2] +5V +12V [2]
Regulation [5] ±5% ±5% [2] ±5% ±5% [2]
Avg idle current DCX [1] [7] 0.39 0.59 0.39 0.59
Maximum starting current
(peak DC) DC 3s [3] 0.62 1.91 0.62 1.91
(peak AC) AC 3s [3] 0.96 3.75 0.98 3.57
Delayed motor start (max)
DC
3s [1] [4] 0.56 0.04 0.56 0.04
Peak operating current:
Typical DC
X [1] [6] 0.48 0.92 0.48 0.91
Maximum DC 3s [1] 0.53 1.00 0.53 0.95
Maximum (peak) DC 3s 1.32 2.80 1.32 2.72
+5 V = 250 mV pp from 100 Hz to 20 MHz.
+12 V = 800 mV pp from 100 Hz to 8 KHz.
450 mV pp from 8 KHz to 20 KHz.
250 mV pp from 20 KHz to 5 MHz.