Seagate Cheetah 15K Product Manual page 30

Table 17:
ST3146756SS
Voltage
Regulation
Avg idle current DCX
Maximum starting current
(peak DC) DC
(peak AC) AC
Delayed motor start (max) DC 3σ
Peak operating current:
Typical DCX
Maximum DC
Maximum (peak) DC
[1] Measured with average reading DC ammeter or equivalent sampling scope. Instantaneous +12V current
peaks will exceed these values. Power supply 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
15,000 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 after OOB and Speed Negotiation completes but before the drive has received the
Notify Spinup primitive.
[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 330 I/Os per second for 450GB models, and
347 I/Os per second for 300GB and 1465GB 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 1.7% 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. No terminator power.
26
(FDE) DC power requirements
ST3146756SS (FDE)
1.5 Gbit mode
Notes (Amps)
+5V
[5] ±5%
[1] [7] 0.49
3σ [3] 0.66
3σ [3] 0.86
[1] [4] 0.60
[1][6] 0.58
3σ [1] 0.59
3σ 1.12
ST3146756SS (FDE)
3 Gbit mode
(Amps) (Amps)
+12V [2] +5V
±5% [2] ±5%
0.55 0.51
1.81 0.69
4.24 0.90
0.04 0.63
0.96 0.60
0.97 0.62
2.32 1.14
Cheetah 15K.6 SAS Product Manual, Rev. B
(Amps)
+12V [2]
±5% [2]
0.55
1.82
4.28
0.04
0.96
0.97
2.36