Seagate ST39205LW/LC manual Conducted noise immunity, Power sequencing, 3 12 V Current profile

24 Cheetah 36XL Product Manual, Rev. E

6.2.1Conducted 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.

+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.

6.2.2Power 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 SCSI bus terminator to ensure proper termination of the peripheral I/O cables. To automatically delay motor start based on the target ID (SCSI ID) enable the Delay Motor Start option and disable the Enable Motor Start option on the J2 connector. See Section 8.1 for pin selection information. To delay the motor until the drive receives a Start Unit command, enable the Enable Remote Motor Start option on the J2 connector.

6.2.312 V - Current profile

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

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 1 of Table 2.

T3 - The spindle is up to speed and the head-arm restraint is unlocked.

T4 - The adaptive servo calibration sequence is performed.

T5 - Calibration is complete and drive is ready for reading and writing.

Note. All times and currents are typical.