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2.9.1
Power consumption
Power requirements for the drives are listed in the table on page 7. Typical power measurements are based on
an average of drives tested, under nominal conditions, using 5.0V and 12.0V input voltage at 25°C ambient
temperature.
• Spinup power
Spinup power is measured from the time of power-on to the time that the drive spindle reaches operating speed.
• Seek mode
During seek mode, the read/write actuator arm moves toward a specific position on the disc surface and does
not execute a read or write operation. Servo electronics are active. Seek mode power represents the worst-
case power consumption, using only random seeks with read or write latency time. This mode is not typical
and is provided for worst-case information.
• Read/write power and current
Read/write power is measured with the heads on track, based on a 16-sector write followed by a 32-msec
delay, then a 16-sector read followed by a 32-msec delay.
• Operating power and current
Operating power is measured using 40 percent random seeks, 40 percent read/write mode (1 write for each
10 reads) and 20 percent drive idle mode.
• Idle mode power
Idle mode power is measured with the drive up to speed, with servo electronics active and with the heads in
a random track location.
• Standby mode
During Standby mode, the drive accepts commands, but the drive is not spinning, and the servo and read/
write electronics are in power-down mode.
Power dissipation (watts)
Example: ST3160022A, 2-disc
Spinup
Idle
Idle* (with offline activity)
Operating 40% r/w, 40% seek, 20% inop.
Seeking
Standby
Sleep
*During periods of drive idle, some offline activity may occur according to the S.M.A.R.T. specification, which may increase acoustic and
power to operational levels.
U Series 9 Product Manual, Rev. D
Average
5V typ
(watts, 25° C)
amps
—
—
7.5
0.482
9.3
0.587
12.0
0.638
12.5
0.412
0.900
0.144
0.900
0.144
12V typ
amps
2.8 (peak)
0.424
0.530
0.739
0.870
0.015
0.015
7
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