Product manual

Barracuda 9 Product Manual, Rev. C 21
6.0 Physical/electrical specifications
This section provides information relating to the physical and electrical characteristics of Barracuda 9 drives.
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’s power connector. The power requirements for single-ended models includes the internal disc
drive SCSI I/O termination. Current values are in Amperes.
Table 2: DC power requirements
[1] Measured with average reading DC ammeter. Instantaneous +12V current peaks will exceed these val-
ues.
[2] A –10% droop is permissible during initial start of spindle, and must return to ±5% before 7,200 rpm is
reached. The ±5% must be maintained after the drive signifies that its power-up sequence has been com-
pleted and that the drive is able to accept selection by the host initiator.
[3] See +12V 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.
[5] See Section 6.2.1 “Conducted Noise Immunity.” Specified voltage tolerance is inclusive of ripple, noise,
and transient response.
[6] At power-up, the motor current regulator limits the 12 volt current to an average value of less than 2.5
amperes, although instantaneous peaks may exceed this value. These peaks should measure 5 msec
duration or less.
[7] Operating condition is defined as a third-stroke seek at OD and Read One track. A command is issued
every 0.062 seconds.
[8] No terminator power. See Section 9.9.
Notes
ST19171N/W/WC
Single-ended
ST19171WD/DC
Differential
Voltage +5 V [8] +12 V +5 V [8] +12 V
Regulation [5] ±5% ±5%[2] ±5% ±5%[2]
Maximum operating current DC3σ [1] 0.93 0.89 1.17 0.89
Average idle current DCX
[1] [9] 0.84 0.73 0.96 0.73
Maximum starting current
(peak DC) DC3σ
(peak AC) AC3σ
[3] [6]
[3]
0.92 2.18
3.1
1.04 2.18
3.1
Delayed motor start (max) DC3σ [1] [4] 0.82 0.08 0.90 0.08
Peak operating current
Typical DCX
Maximum DC3σ
Maximum (Peak) DC3σ
[1] [7]
[1]
0.92
0.93
1.00
0.84
0.89
1.8
1.12
1.17
1.89
0.84
0.89
1.8
Track following at
OD DCX
ID DCX
[1]
[1]
0.84
0.83
0.73
0.76
0.96
0.94
0.73
0.76
Read Track
OD DC3σ
AC3σ
[1] [11] 0.96
1.10
0.78
0.97
1.49
1.99
0.78
0.97
Seeking (Typical) DCX
Maximum DC3σ
Maximum (Peak) AC3σ
[1] [10]
[1]
0.91
0.92
0.96
1.06
1.1
1.8
0.99
1.05
1.77
1.06
1.1
1.8