Conducted Noise Immunity; Power Sequencing; 12V Current Profile; Power Dissipation - Seagate ST34501FC Cheetah 4LP Product Manual

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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.
+5V
0 to 100 kHz 150mV
100 kHz to 10 MHz 100mV
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

12V current profile

Figure 3 identifies the drive +12V current profile. The current during the various times is as shown.
3
2
1
0
Figure 3. Typical Cheetah 4LP 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 starting and operating current require-
ments.
6.3

Power dissipation

Typical seek and read power dissipation is 18.3 watts (63.0 BTUs per hour) of DC power average at nominal
voltages. Typical power dissipation under idle conditions is 15.5 watts (53 BTUs per hour).
6.4

Environmental limits

Temperature and humidity values experienced by the drive must be such that condensation does not occur on
any drive part. Altitude and atmospheric pressure specifications are referenced to a standard day at 58.7°F
(14.8°C). Maximum wet bulb temperature is 82°F (28°C).
+12V (with spindle motor not running)
150mV
100mV
+12 Volt Current during spindle start
Envelope of waveform
Average value of waveform
T0 T1 T2
0 2 4 6
Seconds
Cheetah 4LP FC Product Manual, Rev. A
T3
8 10 12 14 16