Seagate ST3146855LW manual ST3146855LC DC power requirements, ST373455LC DC power requirements

Table 4:	ST3146855LC DC power requirements
			Notes		LVD mode
Voltage				+5 V		+12 V
Regulation			[5]	±5%		±5%[2]
Average idle current DC		X	[1][6]	0.71		0.57
Maximum starting current
(peak DC) DC		3σ	[3]	0.74		1.94
(peak AC) AC		3σ	[3]	1.04		3.32
Delayed motor start (max) DC		3σ	[1][4]	0.56		0.03
Peak operating current
DC		X	[1]	0.67		0.88
Maximum DC		3σ	[1]	0.68		0.94
Maximum (peak) DC		3σ		1.42		2.50

Table 5:	ST373455LC DC power requirements
			Notes		LVD mode
Voltage				+5 V		+12 V
Regulation			[5]	±5%		±5%[2]
Average idle current DC		X	[1][6]	0.69		0.42
Maximum starting current
(peak DC) DC		3σ	[3]	0.72		1.94
(peak AC) AC		3σ	[3]	1.00		3.32
Delayed motor start (max) DC		3σ	[1][4]	0.56		0.03
Peak operating current
DC		X	[1]	0.67		0.78
Maximum DC		3σ	[1]	0.68		0.82
Maximum (peak) DC		3σ		1.40		2.38

[1]Measured with average reading DC ammeter or equivalent sampling scope. Instantaneous current peaks will exceed these values. Power supply at nominal voltage. Number of drives tested = 6, 35 Degrees C ambient.

[2]For +12 V, a –10% tolerance is permissible during initial start of spindle, and must return to ±5% before 15,000 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 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 Section 7.2.1 “Conducted Noise Immunity.” Specified voltage tolerance is inclusive of ripple, noise, and transient response.

[6]During idle, the drive heads are relocated every 60 seconds to a random location within the band from three-quarters to maximum track.

General Notes for Tables 3, 4, and 5:

1.Minimum current loading for each supply voltage is not less than 1.2% 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

Cheetah 15K.5 SCSI Product Manual, Rev. J 23