Seagate ST9146802SS manual ST973402SS DC power requirements, General DC power requirement notes

Table 13: ST973402SS DC power requirements

			ST973402SS		ST973402SS
			1.5 Gbit mode		3.0 Gbit mode
		Notes	(Amps)	(Amps)	(Amps)	(Amps)
Voltage			+5V	+12V [2]	+5V	+12V [2]
Regulation		[5]	±5%	±5% [2]	±5%	±5% [2]
		[1] [7]	0.81	0.13	0.79	0.12
Avg idle current DCX
Maximum starting current
(peak DC) DC	3σ	[3]	0.88	1.38	0.87	1.38
(peak AC) AC	3σ	[3]	1.25	1.91	1.36	1.91
	3σ
Delayed motor start (max) DC		[1] [4]	0.66	0.03	0.69	0.03
Operating current:
		[1] [6]	0.65	0.31	0.81	0.34
Typical DCX
Maximum DC	3σ	[1]	0.79	0.37	0.84	0.39
Maximum (peak) DC	3σ		1.41	1.17	1.43	1.17

Gen 3.5 LPSS measured data (latest available) plus 12V max start current margins of .15A for DC and .20A for AC. All others have 10% margin added.

[1]Measured with average reading DC ammeter. Instantaneous +12V current peaks will exceed these val- ues. 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 9,936 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 2.

[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.

[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 Savvio 10K.2 SAS Product Manual, Rev. B