Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate
Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate
Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate
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24 <strong>Barracuda</strong> <strong>18LP</strong> Product Manual, Rev. E<br />
6.4 Environmental limits<br />
Temperature and humidity values experienced by the drive must be such that condensation does not occur on<br />
any drive part. Altitude and atmospheric pressure specifications are referenced to a standard day at 58.7°F<br />
(14.8°C). Maximum Wet Bulb temperature is 82°F (28°C).<br />
6.4.1 Temperature<br />
a. Operating<br />
With cooling designed to maintain the case temperatures of Table 3, Column 2, the drive meets all specifications<br />
over a 41°F to 122°F (5°C to 50°C) drive ambient temperature range with a maximum temperature<br />
gradient of 36°F (20°C) per hour. The enclosure for the drive should be designed such that the temperatures<br />
at the locations specified in Table 3, column 1 are not exceeded. Air flow may be needed to achieve<br />
these temperature values (see Section 8.3 and 8.3.1). Operation at case temperatures [4] above these values<br />
may adversely affect the drives ability to meet specifications.<br />
The MTBF specification for the drive is based on operating in an environment that ensures that the case<br />
temperatures specified in Table 3, column 2 are not exceeded. Occasional excursions to drive ambient temperatures<br />
of 122°F (50°C) or 41°F (5°C) may occur without impact to specified MTBF. Air flow may be<br />
needed to achieve these temperatures (see Section 8.3.1). Continual or sustained operation at case temperatures<br />
above these values may degrade MTBF.<br />
To confirm that the required cooling for the <strong>Barracuda</strong> electronics and HDA is provided, place the drive in its<br />
final mechanical configuration, perform random write/read operations. After the temperatures stabilize,<br />
measure the case temperature of the components listed in Table 3 (see notes [2] and [3]).<br />
Operation of the drive at the maximum case temperature is intended for short time periods only. Continuous<br />
operation at the elevated temperatures will reduce product reliability.<br />
Table 3:<br />
PCBA (Printed Circuit Board Assembly) and HDA temperatures<br />
(temporary values from <strong>Barracuda</strong> 18)<br />
Column 1<br />
Maximum case [4]<br />
temperatures (°C)<br />
operating (50° ambient) [2]<br />
Column 2<br />
Maximum allowable<br />
case [4] temperatures (°C)<br />
to meet MTBF spec.<br />
Items in<br />
Figure 4<br />
HDA [3] 60 45<br />
U2 (read channel) 110 90<br />
U5 (SCSI controller) 118 98<br />
U11 (servo demod) 105 85<br />
U15 (servo ASIC) 100 80<br />
Note.<br />
[1] Section 8.3.1 describes the air-flow patterns to be used to meet case temperatures in column 2. Air<br />
flow should be opposite that shown in Section 8.3.1. Air velocity should be adequate to ensure that the<br />
case temperatures in Column 2 are not exceeded during drive operation.<br />
[2] The temperatures in Column 1 are calculated and may not reflect actual operating values. Sufficient<br />
cooling air may be required to ensure that these values are not exceeded.<br />
[3] Measure HDA temp at point labeled “HDA” on Figure 4.<br />
[4] PCBA mounted integrated circuit case.<br />
b. Non-operating<br />
–40° to 158°F (–40° to 70°C) package ambient with a maximum gradient of 45°F (25°C) per hour. This<br />
specification assumes that the drive is packaged in the shipping container designed by <strong>Seagate</strong> for use with<br />
drive.