Conducted Noise Immunity; Power Sequencing; Current Profiles; Figure 3. Typical St373405Fc Drive +12V Current Profile - Seagate Cheetah ST336605FC/FCV Product Manual

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4. Parameters, other than spindle start, are measured after a 10-minute warm up.
5. No terminator power.
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

Current profiles

Figure 3 identifies the drive +12V 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 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.
3.0
A
2.0
1.0
0.0
T0
Figure 3. Typical ST373405FC drive +12V current profile
+12V
150mV
100mV
+12 Volt Current during spindle start – Typical Amperes
Envelope of waveform
Average value of waveform
T1 T2 T3 T4
0 2 4
Cheetah 73LP FC Product Manual, Rev. D
6 8 10 12
Seconds
14 16