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Product Manual - Hawk 2 Family SCSI-2 (Volume 1), Rev. C
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7.0
Physical/electrical specifications
7.1
AC power requirements: None
7.2
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.
Voltage
Regulation [5]
Maximum Operating Current [1]
Typical Idle Current [1] [3]
Maximum Starting Current (Peak)
Delayed Motor Start (Max) [4]
Peak Operating Current [6]
[1] Measured with average reading DC ammeter. Instantaneous +12 V currentpeaks will exceed these values.
[2] A droop of up to -10% is permissible during power up. 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 level T6 in Figure 7.2.2-1.
[4] This condition occurs when the Motor Start Option is enabled and the drivehas not yet received a Start Mo-
tor command.
[5] See paragraph 7.2.1 "Conducted Noise Immunity".
[6] Instantaneous peaks less than 5 msec. in duration are allowed.
General Notes from Table 7.2-1:
1. At powerup, the motor current regulator limits the 12 volt current to a peak value of less than 2.4 amperes,
although instantaneous peaks may exceed this value. These peaks should measure 5 msec. duration or
less.
2. Operating condition is defined as Random Seek Reads of 64 blocks.
3. Minimum current loading for each supply voltage is not less than 30% of the maximum operating current
shown.
4. The +5 and +12 volt supplies shall employ separate ground returns.
5. 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 starting
current must be available to each device.
Table 7.2-1. DC power requirements
Single Ended
+5 V
+5%
1.0 A
0.42 A
0.8 A
0.6 A
Typ. [1]
0.76 A
Max. [1]
1.0 A
Max. (Peak)
-
Differential
+12 V
+5 V
+5%[2]
+5%
1.0 A
1.2 A
0.57 A
0.57 A
2.4 A
0.9 A
0.4 A
0.6 A
0.58 A
1.01 A
1.0 A
1.2 A
2.4 A
-
21
+12 V
+5%[2]
1.0 A
0.57 A
2.4 A
0.4 A
0.58 A
1.0 A
2.4 A
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