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20 Elite 23 Product Manual, Rev. A

[9] Seeking is defined as a third-stroke seek at OD. A command is issued every 20 msec.

[10] Read track is defined as repeat reads of track 15 with a duty cycle of 63% for narrow single-ended.

General Notes from Table 2:

1. Minimum current loading for each supply voltage is not less than 4% of the maximum operating current

shown.

2. The +5 and +12 volt supplies shall employ separate ground returns.

3. 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 start-

ing current must be available to each device.

6.2.1 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 con-

nector.

6.2.2 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 device to ensure proper

termination of the peripheral I/O cables. To automatically delay motor start based on the target ID (SCSI ID)

enable the Spinup Delay option (install jumper) and disable the Start Command option (remove jumper) on the

J4B connector. See Section 8.1 for pin selection information. To delay the motor until the drive receives a Start

Unit command, enable the Enable Motor Start option on the J4B connector.

6.2.3 12 V current profile

Figure 3 identifies the drive +5 V and +12 V current profile. The current during the various times is as shown.

Figure 3. Typical Elite 23 drive +5 V and +12 V current profile

+5 V = 150 mV pp from 0 to 100 kHz and 100 mV pp from 100 kHz to 10 MHz.

+12 V = 150 mV pp from 0 to 100 kHz and 100 mV pp from 100 kHz to 10 MHz.

T0 - Power is applied to the drive.

T1 - Controller self-tests are performed.

T2 - Spindle begins to accelerate under current limiting after performing drive internal diagnostics. See

Note 9 of Table 2.

0 5 10 15 20 25

Time (seconds)

30 35 40 45

+12V

Current

(amps)

Minimum

Peak

Nominal

(average)

1 2 ... 25 26 27 28 29 30 31 32 33 34 35 ... 83 84

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Seagate Elite 9 Handbuch Seite 30