Conducted Noise Immunity; Power Sequencing; Current Profile - Seagate HAWK 4 Series Product Manual

Product Manual - Hawk 4 Family (Wide) SCSI-2 (Volume 1), Rev. E
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7.2.1

Conducted noise immunity

Noise is specified as a periodic and random distribution of frequencies covering a band from DC to 10 mHz.
Maximum allowed noise values given below are peak to peak measurements and apply at the drive power
connector.
+5 V = 150 mV pp from 0 to 50 kHz and 45 mA pp from 50 kHz to 10 mHz.
+12 V = 150 mV pp from 0 to 50 kHz and 60 mA pp from 50 kHz to 10 mHz.
7.2.2

Power sequencing

The drive does not require power sequencing. The drive protects against inadvertent writing during power up
and down. Daisy-chain operation requires that power be maintained on the terminated drive to ensure proper
termination of the peripheral I/O cables. For the benefit of the system power supply, the drive power up can be
delayed using the motor start delay option. See Section 10.1.
7.2.3 12 V - current profile
Figure 7.2.2-1 identifies the drive +5 V and +12 V current profile. The current during the various times is as
shown:
T - Power is applied to the drive.
T1 - Controller self tests are performed.
T2 - Spindle begins to accelerate under current limiting after performing internal diagnostics. See Note 1
of Table 7.2-1.
T3 - The spindle is up to speed and the Head-Arm restraint is unlocked.
T4 - The heads move from the landing zone to the data area.
T5 - The adaptive calibration sequence is performed.
T6 - Calibration is complete and the drive is ready for reading and writing.
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