Hitachi HDS721025CLA382 User Manual
Hitachi hard disk drive specifications
31
Power supply current of
1 Disk models
1 Disk models
+5 Volts [mA]
+12 Volts [mA]
Total
[W]
(values in milliamps. RMS)
Pop Mean
Pop Mean
Idle average
220
210
3.6
Idle ripple (peak-to-peak)
200
300
Low RPM Idle
160
90
1.9
Low RPM Idle Ripple
100
250
Unload Idle average
160
200
3.2
Unload Idle Ripple
100
300
Random R/W average
1
(Quiet Seek)
350
400
6.6
Random R/W peak(Quiet Seek)
1100
1200
Start up (max)
1100
1900
Standby average
160
7
0.9
Sleep average
160
7
0.9
Table 19 Power supply current of 1 Disk model
1
Random R/W : 35 IOPS / 16 Blocks Random Write and Random Read
6.3.3
Power supply generated ripple at drive power connector
Maximum
(mV pp)
MHz
+5V DC
200
0-10
+12V DC
250
0-10
Table 20 Power supply generated ripple at drive power connector
During drive start up and seeking 12-volt ripple is generated by the drive (referred to as dynamic loading). If the
power of several drives is daisy chained together, the power supply ripple plus the dynamic loading of the other
drives must remain within the above regulation tolerance. A common supply with separate power leads to each
drive is a more desirable method of power distribution.
power of several drives is daisy chained together, the power supply ripple plus the dynamic loading of the other
drives must remain within the above regulation tolerance. A common supply with separate power leads to each
drive is a more desirable method of power distribution.
To prevent external electrical noise from interfering with the performance of the drive, the drive must be held by
four screws in a user system frame which has no electrical level difference at the four screws position and has
less than ±300 millivolts peak to peak level difference to the ground of the drive power connector
four screws in a user system frame which has no electrical level difference at the four screws position and has
less than ±300 millivolts peak to peak level difference to the ground of the drive power connector
.