Barracuda 4LP Product Manual, Rev. D
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6.3
Power dissipation
For drives with single ended interface circuits, typical operating random read power dissipation is 12.9 watts
(44 BTUs per hour) of DC power average at nominal voltages. Typical power dissipation under idle conditions is
8.8 watts (30 BTUs per hour).
For drives with differential interface circuits, typical operating random read power dissipation is 14.4 watts (49
BTUs per hour) of DC power average at nominal voltages. Typical power dissipation under idle conditions is 10
watts (34 BTUs per hour).
6.4
Environmental limits
Temperature and humidity values experienced by the drive must be such that condensation does not occur on
any drive part. Altitude and atmospheric pressure specifications are referenced to a standard day at 58.7°F
(14.8°C). Maximum Wet Bulb temperature is 82°F (28°C).
6.4.1
Temperature
a. Operating
The drive meets all specifications over a 41°F to 122°F (5°C to 50°C) drive ambient temperature range with
a maximum temperature gradient of 36°F (20°C) per hour. The enclosure for the drive should be designed
such that the temperatures at the locations specified in Table 3, column 1 are not exceeded. Air flow may be
needed to achieve these temperature values. Operation at case temperatures [3] above these values may
adversely affect the drives ability to meet specifications.
The MTBF specification for the drive is based on operating in an environment that ensures that the case
temperatures specified in Table 3, column 2 are not exceeded. Occasional excursions to drive ambient tem-
peratures of 122°F (50°C) or 41°F (5°C) may occur without impact to specified MTBF. To achieve the speci-
fied MTBF, the values of Table 3, column 2 must be considered maximum average operating case
temperatures and the enclosure for the drive should be designed such that those temperature values are
not exceeded. Air flow may be needed to achieve these temperatures. Continual or sustained operation at
case temperatures above these values may degrade MTBF.
To confirm that the required cooling for the Barracuda electronics and HDA is provided, place the drive in its
final mechanical configuration, perform random write/read operations typical of expected normal operation.
After the temperatures stabilize, measure the case temperature of the components listed in Table 3.
Operation of the drive at the maximum case temperature is intended for short time periods only. Continuous
operation at the elevated temperatures will reduce product reliability. See also Section 8.3, “Cooling.”
Table 3:
PCB and HDA temperatures
Note.
[1]
The temperatures in Column 1 are calculated and may not reflect actual operating values. Sufficient
cooling air may be required to ensure that these values are not exceeded.
[2]
Measure HDA temp at point labeled “HDA” on Figure 4.
[3]
PCB mounted integrated circuit case.
b. Non-Operating
–40° to 158°F (–40° to 70°C) package ambient with a maximum gradient of 45°F (25°C) per hour. This
specification assumes that the drive is packaged in the shipping container designed by Seagate for use with
drive.
Items in
Figure 4
Column 1
Maximum Case
Temperatures (°C)
Operating (50° Ambient) [1]
Column 2
MTBF
1 Million Hours
Case Temperatures (°C)
HDA [2]
60
45
U2 [3]
81
61
U4 [3]
84
64
U5 [3]
90
70
U13 [3]
79
59
