Table 23.Power Supply Generated Ripple At Drive Power Connector - Hitachi 7K250 - Deskstar - Hard Drive Specifications

Power supply current of
40GB and 80GB models
values in milliamps, RMS
Start up (max)
Standby average
Sleep average
6.3.3 Power supply generated ripple at drive power connector
Table 23: Power supply generated ripple at drive power connector
Maximum (mV pp)
+5 V dc 100
+12 V dc 150
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.
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.
+5 Volts (mA)
Pop mean Std
dev
870 50
140 9
100 8
MHz
0-10
0-10
Deskstar 7K250 Hard Disk Drive Specification
+12 Volts (mA)
Pop mean Std dev
1700 50
20 3
20 3
31
Total (W)
0.9
0.7