Hitachi 7K250 Specifications - Page 45
Power supply generated ripple at drive power connector
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UPC - 000004558972
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Power supply current of 40GB and 80GB models values in milliamps, RMS +5 Volts (mA) Pop mean Std dev Start up (max) 870 50 Standby average 140 9 Sleep average 100 8 +12 Volts (mA) Pop mean Std dev 1700 50 20 3 20 3 Total (W) 0.9 0.7 6.3.3 Power supply generated ripple at drive power connector Table 23: Power supply generated ripple at drive power connector Maximum (mV pp) MHz +5 V dc 100 0-10 +12 V dc 150 0-10 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. Deskstar 7K250 Hard Disk Drive Specification 31
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