Table 38.Power Supply Generated Ripple At Drive Power Connector - Hitachi T7K250 - Deskstar - Hard Drive Specifications

Power supply current of 160
GB and 250 GB model
(SATA models)
2
Silent R/W average
Silent R/W peak
Start up (max)
Standby average
Sleep average
7.3.3 Power supply generated ripple at drive power connector
Table 38: 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
680 9
1450 30
1200 50
350 9
300 8
MHz
0-10
0-10
Deskstar T7K250 Hard Disk Drive Specification
+12 Volts (mA)
Pop mean Std dev
400 12
1000 40
1880 50
15 2
15 2
56
Total (W)
8.2
1.93
1.68