Power Dissipation; Environmental Limits; Temperature - Seagate ST34520N - Medalist 4.55 GB Hard Drive Product Manual

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6.3

Power dissipation

For drives with single-ended interface circuits, typical operating random read/write power dissipation is 14.1
watts (48.1 BTUs per hour) of DC power average at nominal voltages. Typical power dissipation under idle con-
ditions is 12.3 watts (42.0 BTUs per hour). Standby power is 4.1 watts (14.0 BTUs per hour).
For drives with low voltage differential interface circuits (LVD), typical operating random read/write power dissi-
pation is 14.6 watts (49.8 BTUs per hour) of DC power average at nominal voltages. Typical power dissipation
under idle conditions is 13.5 watts (46.0 BTUs per hour). Standby power is 4.5 watts (15.3 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 131°F (5°C to 55°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 131°F (55°C) or 41°F (5°C) may occur without impact to specified MTBF. 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 Medalist Pro 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.
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.
Table 3: PCB and HDA temperatures
Column 1
maximum case [3]
Items in temperatures operating
Figure 4 (55°C ambient) [1]
U4 105°C
U60 100°C
U80 90°C
U90 95°C
U94 80°C
HDA 60°C
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. Large thermal gradients
should be avoided.
[2] No point anywhere on the HDA surface should exceed this value.
[3] PCB mounted integrated circuit case.
Medalist Pro Product Manual, Rev. D
Column 2
maximum allowable
case [3] temperature (°C)
to meet MTBF spec.
85°C
80°C
70°C
75°C
60°C
50°C