Start Up Current - IBM DDRS-39130 - Ultrastar 9.1 GB Hard Drive Specifications

Figure 37. Power Supply Generated Ripple at Drive Power Connector
+ 5 V DC
+ 1 2 V DC
During drive start up and seeking, 12 volt ripple is generated by the drive (referred to as dynamic loading). If
several files have their power daisy chained together then the power supply ripple plus other drive's dynamic
loading must remain within the regulation tolerance of ± 0.5%. 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 drive's performance, 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 milivolts peak to peak level difference to the drive power connector ground.

6.6.1 Start Up Current

Figure 38. Typical Current Wave Form of 12V at Start Up of DDRS-34560
42
O E M Spec. of DDRS-3xxxx
Maximum
100 [ mV pp]
150 [ mV pp]
Notes
0-10 [ MHz]
0-10 [ MHz]