Environmental Limits; Temperature - Seagate ST318203LW Product Manual

Cheetah 18LP Product Manual, Rev. F
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
With cooling designed to maintain the case temperatures of Table 3 (ST318203 and ST39103 models) or
Table 4 (ST318233 and ST39133 models), 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
(ST318203 and ST39103 models) or Table 4 (ST318233 and ST39133 models) are not exceeded. Air flow
may be needed to achieve these temperature values (see Section 8.3 and 8.3.1). Operation at case temper-
atures 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 (ST318203 and ST39103 models) or Table 4 (ST318233 and ST39133
models) are not exceeded. Occasional excursions to drive ambient temperatures of 122°F (50°C) or 41°F
(5°C) may occur without impact to specified MTBF. Air flow may be needed to achieve these temperatures
(see Section 8.3.1). Continual or sustained operation at case temperatures above these values may
degrade MTBF.
To confirm that the required cooling for the electronics and HDA is provided, place the drive in its final
mechanical configuration, perform random write/read operations. After the temperatures stabilize, measure
the case temperature of the components listed in Table 3 (ST318203 and ST39103 models) or Table 4
(ST318233 and ST39133 models). See note [2].
The maximum allowable HDA case temperature is 60°C. Operation of the drive at the maximum case tem-
perature is intended for short time periods only. Continuous operation at the elevated temperatures will
reduce product reliability.
Table 3: PCBA and HDA temperatures (ST318203 and ST39103 models)
Items in Maximum allowable case
Figure 15 temperature (
HDA [2] 60
1 80
2 68
3 76
4 71
Table 4: PCBA and HDA temperatures (ST318233 and ST39133 models)
Items in Maximum allowable case
Figure 15 temperature (
HDA [2] 60
1 80
2 73
3 81
4 71
Notes.
[1] Section 8.3.1 describes the air-flow patterns used when generating the 1 million hours MTBF guide-
lines in column 2. Air flow was opposite that shown in Section 8.3.1. Local air velocity was 0.92 m/sec
(180 lfpm). Inlet air temperature to the drive was 77°F (25°C), plus 9°F (5°C) temperature rise in the
test enclosure (86°F/30°C ambient local to the drive).
[2] Measure HDA temp at point labeled "HDA" on Figure 15.
[3] PCB mounted integrated circuit case.
Maximum allowable case [3]
°
C) operating temperatures (°C) to meet MTBF spec.
45
60
48
56
51
Maximum allowable case [3]
°
C) operating temperatures (°C) to meet MTBF spec.
45
60
53
61
51
27