Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate

20 Barracuda 18LP Product Manual, Rev. E
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 connector.
+5 V = 150 mV pp from 0 to 50 kHz and 100 mV pp from 50 kHz to 10 MHz.
+12 V = 150 mV pp from 0 to 50 kHz and 100 mV pp from 50 kHz to 10 MHz.
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 drive 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 Motor Start option on the J2 connector.
6.2.3 Current profile
Figures 3a and 3b identify the drive +5 V and +12 V current profile. The current during the various times is as
shown:
T -
T1 -
T2 -
T3 -
T4 -
T5 -
Power is applied to the drive.
Controller self tests are performed.
Spindle begins to accelerate under current limiting after performing drive internal
diagnostics. See Note 1 of Table 2.
The heads move from the landing zone to the data area.
The adaptive servo calibration sequence is performed.
Calibration is complete and the drive is ready for reading and writing.
Note.
All times and currents are typical. See Table 2 for maximum current requirements.
3.5
3.0
2.5
2.0
T
T3
T1 T2 T4
AC
Component
T5
+12V
Current
(amps)
1.5
1.0
0.5
0.0
Nominal (average) DC curve
0.0 2 4 6 8 10 12 14 16 18 20 22 24
TIME (seconds)
Figure 3a.
Typical Barracuda 18LP family drive +12 V current profile