Conducted Noise Immunity; Power Sequencing - Seagate ST15150N - Barracuda 4.3 GB Hard Drive Product Manual

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7.2.1
7.2.2
ST15150N/ND/W/WD/WC/DC Product Manual, Rev. D
[4] This condition occurs when the Motor Start Option is enabled and the drive
has not yet received a Start Motor command.
[5] See Section 7.2.1 "Conducted noise immunity." Specified voltage toler-
ance is inclusive of ripple, noise, and transient response.
[6] At power-up, the motor current regulator limits the 12V current to an
average value of less than 2.18A, although instantaneous peaks may
exceed this value. These peaks should measure 5 msec duration or less.
[7] Minimum current loading for each supply voltage is not less than 3% of the
maximum operating current shown.
[8] The 5V and 12V supplies employ separate ground returns.
No terminator power. See Section 11.7.3.4.
[9] Where power is provided to multiple drives from a common supply, careful
consideration for individual drive power requirements should be noted.
Where multiple units are powered on simultaneously, the peak starting
current must be available to each device.
[10] Operating condition is defined as a third stroke seek at OD and read one
track. A command is issued every 0.063 sec for N/W/WD/WC/DC drives
(0.075 sec for ND drives).
[11] No terminator power. See 11.7.3.4.
[12] All power saving features enabled; ASA II code only.
[13] Seeking is defined as a third stroke seek at OD. A command is issued every
20 msec.
[14] Read track is defined as repeat reads of track 15 with a 60% duty cycle for
N/ND drives, 74% duty cycle for W drives, 32% duty cycle for WC drives,
44% duty cycle for WD drives, and 50% duty cycle for DC drives.

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's power
connector.
0 to 100 kHZ
5V 150 mV
12V 150 mV

Power sequencing

The drive does not require power sequencing. The drive protects against
inadvertent writing during power-up and down. Daisy-chain operation re-
quires that power be maintained on the terminated device to ensure proper
termination of the peripheral I/O cables.
To automatically delay motor start based on the target ID (SCSI ID), select
the Delay Motor Start option and deselect the Enable Motor Start option on
the J4 connector. See Section 10.1 for pin selection information.
To delay the motor until the drive receives a Start Unit command, select the
Enable Motor Start option on the J4 connector.
100 kHz to 10 MHz
100 mV
100 mV