Hitachi 7K400 Specifications - Page 66
Power supply generated ripple at drive power connector
UPC - 000053412935
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Table 49: Power supply current of SATA model Power supply current of SATA model +5 Volts [mA] +12 Volts [mA] (values in milliamps. RMS) Idle average Idle ripple (peak-to-peak) Low RPM Idle Low RPM Idle Ripple Unload Idle average Unload Idle Ripple Random R/W average2 Random R/W peak Silent R/W average Silent R/W peak Start up (max) Standby average Sleep average Pop Mean 470 250 300 220 300 220 670 1600 710 1600 1190 280 220 Std Dev 12 40 7 30 7 35 9 50 9 50 50 9 8 Pop Mean 600 600 280 380 480 600 850 2100 660 1350 2000 20 20 Std Dev 12 20 10 20 13 20 20 50 15 40 75 3 3 Total [W] 9.6 4.9 7.3 13.6 11.5 1.6 1.3 7.3.3 Power supply generated ripple at drive power connector Table 50: 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 7K400 Hard Disk Drive Specification 52