Power Supply Generated Ripple At Drive Power Connector; Start Up Current; Figure 52. Power Supply Generated Ripple At Drive Power Connector; Figure 53. Typical Current Form Of 12V At Start Up Of Dtla-305010/305020/305030/ 305040 - IBM DTLA-305040 - Deskstar 41.1 GB Hard Drive Specifications

7.5.3 Power supply generated ripple at drive power connector

+5V DC
+12V DC

Figure 52. 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.
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 .

7.5.4 Start Up Current

7.5.4.1 DTLA-305010/305020/305030/305040
Figure 53. Typical Current Form of 12V at Start Up of
Maximum (mV pp)
100
150
DTLA-305010/305020/305030/305040
Deskstar 40GV & 75GXP hard disk drive specifications
MHz
0-10
0-10
50