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Cheetah 10K.6 FC Product Manual, Rev. B 25
ST336607FC
Typical power dissipation under idle conditions is 7.89 watts (26.9 BTUs per hour).
To obtain operating power for typical random read operations, refer to the following I/O rate curve (see Figure
9). Locate the typical I/O rate for a drive in your system on the horizontal axis and read the corresponding +5
volt current, +12 volt current, and total watts on the vertical axis. To calculate BTUs per hour, multiply watts by
3.4123.
Figure 11. ST336607FC DC current and power vs. input/output operations per second
Note. Values shown are for operation at 2 Gb, for operation at 1 Gb, reduce the +5V by.10Amps. The +12V
current values are not affected by loop speed.
Figure 12. 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).
6.3.1 Temperature
a. Operating
With cooling designed to maintain the case temperature, 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 these temperatures are not exceeded.
Air flow may be needed to achieve these temperature values (see Section 8.4). Operation at HDA case tem-
peratures 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 HDA
case temperatures are not exceeded. Occasional excursions to drive ambient temperatures 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 HDA case temperatures above these values may
degrade MTBF. The maximum allowable continuous or sustained HDA case temperature for the rated
MTBF is 122°F (50°C).
To confirm that the required cooling for the HDA is provided, place the drive in its final mechanical configu-
ration, perform random write/read operations. After the temperatures stabilize, measure the case tempera-
ture.
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.
ST336607 FC CURRENT/POWER vs THROUGHPUT (2 gig)
Random 8 Block Reads
0.300
0.500
0.700
0.900
1.10 0
1.3 00
1.5 00
1.7 00
0.0 50.0 100.0 150.0 200.0 250.0
I/Os per Second
Amperes
4.00
6.00
8.00
10 .0 0
12 .0 0
14 .0 0
16 .0 0
18 .0 0
Power (watts)
5Volt A
12 V o l t A
Watts