Seagate Cheetah 9LP ST39102FC, Product Manual

Page: 30 / 76

20 Cheetah 9LP FC Product Manual, Rev. C
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.
6.2.2 Power sequencing
The drive does not require power sequencing. The drive protects against inadvertent writing during power-up
and down.
6.2.3 Current profiles
Figure 3 identifies the drive +12V current profile. The current during the various times is as shown:
Figure 3. Typical Cheetah 9LP FC drive +12V current profile
T0 Power is applied to the drive.
T1 Controller self-tests are performed.
T2 Spindle begins to accelerate under current limiting after performing internal diagnostics.
T3 Spindle is up to speed and the Head-Arm restraint is unlocked.
Note: All times and currents are typical. See Table 1 for maximum current requirements.
6.3 Power dissipation
Typical seek power dissipation is 15.6 watts (53 BTUs per hour) of DC power average at nominal voltages. Typ-
ical power dissipation under idle conditions is 13.7 watts (47 BTUs per hour).
+5V +12V (with spindle motor not running)
0 to 100 kHz 150mV 150mV
100 kHz to 10 MHz 100mV 100mV
0 5 10 15 20 25 30 35 40
0
.5
1
1.5
2
2.5
Seconds
Amps
Average value of waveform
Envelope of waveform
+12 Volt Current during spindle start – Typical Amperes
T0 T3
T1
T2