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Cheetah 36LP Product Manual, Rev. B
6.0
Physical/electrical specifications
This section provides information relating to the physical and electrical characteristics of the Cheetah 36LP
drive.
6.1
AC power requirements
None.
6.2
DC power requirements
The voltage and current requirements for a single drive are shown in the following table. Values indicated apply
at the drive power connector. The table shows current values in Amperes.
Table 2:
DC power requirements
Voltage
Regulation
Average idle current DCX
Maximum starting current
(peak DC) DC
(peak AC) AC
Delayed motor start (max) DC
Peak operating current
DCX
Maximum DC
Maximum (peak) DC
[1]
Measured with average reading DC ammeter or equivalent sampling scope. Instantaneous current peaks
will exceed these values. Power supply at nominal voltage. N = 6, 22 Degrees C ambient.
[2]
For +12 V, a –10% tolerance is permissible during initial start of spindle, and must return to ±5% before
10,033 rpm is reached. The ±5% must be maintained after the drive signifies that its power-up sequence
has been completed and that the drive is able to accept selection by the host initiator.
[3]
See +12 V current profile in Figure 3.
[4]
This condition occurs when the Motor Start Option is enabled and the drive has not yet received a Start
Motor command.
[5]
See Section 6.2.1 "Conducted Noise Immunity." Specified voltage tolerance is inclusive of ripple, noise,
and transient response.
[6]
Operating condition is defined as random 8 block reads at 186 I/Os per second. Current and power speci-
fied at nominal voltages. Decreasing +5 volts by 5% increases 5 volt current by 2.6%. Decreasing +12
volt supply by 5% increases 12 volt current by 2%.
[7]
During idle, the drive heads are relocated every 60 seconds to a random location within the band from
track zero to one-fourth of maximum track.
General Notes from Table 2:
1. Minimum current loading for each supply voltage is not less than 1.3% of the maximum operating current
shown.
2. The +5 and +12 volt supplies shall employ separate ground returns.
3. Where power is provided to multiple drives from a common supply, careful consideration for individual drive
power requirements should be noted. Where multiple units are powered on simultaneously, the peak start-
ing current must be available to each device.
4. Parameters, other than spindle start, are measured after a 10-minute warm up.
5. No terminator power.
ST336704
Notes
SE mode
+5 V
+12 V
+5 V
[5]
±5%
±5%[2] ±5%
[1][7] 0.79
0.63
0.86
[3]
0.86
2.24
0.93
[3]
1.08
3.8
1.1
[1][4] 0.68
0.03
0.75
[1][6]
0.84
1.12
0.94
[1]
0.86
1.25
0.96
1.2
2.64
1.4
LVD mode
+12 V
±5% [2]
0.63
2.24
3.8
0.03
1.12
1.25
2.64
21
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