Heat/Power Dissipation; Environmental Limits; Temperature - Seagate ST3620N Product Manual

22
_____________________________________________________________________________________
7.3

Heat/power dissipation

For drives with single ended interface circuits, typical operating random read power dissipation is 8.5 watts (29
BTUs per hour) of DC power average at nominal voltages. Typical power dissipation under idle conditions is
6.5 watts (22.2 BTUs per hour).
7.4

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).
7.4.1

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 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 7.4.1-1, column 1 are not exceeded. Air flow may be
needed to achieve these temperature values. Operation at case temperatures above these values may
adversely affect the drive's ability to meet specifications.
The MTBF specification for the drive is based on operating at an ambient temperature of 95°F (35°C).
Occasional excursions to drive ambient temperatures of 50°C or 5°C may occur without impact to
specified MTBF. To achieve the specified MTBF, the values of Table 7.4.1-1 Column 2 must be considered
maximum average operating case temperatures. Continual or sustained operation at case temperatures
above the values shown in Column 2 may degrade MTBF.
Items
in
Figure
7.4.1-1
HDA
U2
U8
Q2
Q13
[1] The temperatures in Column 2 were made in an enclosed box with no air flow at a pressure of one
atmosphere.
[2] No point on the HDA top cover should exceed the maximum temperature. Measure at a point shown in
Figure 7.4.1-1.
[3] Ambient temperature measured at the side of the drive 0.25" (6.4 mm) from the case. Air flow is 3.5 cfm,
min.
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.
Product Manual - Hawk 1LP Family SCSI-2 (Volume 1), Rev. D
Table 7.4.1-1. PCB and HDA temperatures
Column 1
Maximum Case
Temperatures (°C)
Operating (50° Ambient) [3]
60 [2]
80
65
64
67
Column 2
Typical Case
Temperatures(°C)
at 35°C Ambient [1]
56
72
50
63
61