Seagate ST3450856SS ユーザーズマニュアル
Cheetah 15K.6 SAS Product Manual, Rev. A
25
15,000 RPM. 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.
completed and that the drive is able to accept selection by the host initiator.
[3]
See +12V current profile in Figure 2.
[4]
This condition occurs after OOB and Speed Negotiation completes but before the drive has received the
Notify Spinup primitive.
Notify Spinup primitive.
[5]
See paragraph 6.2.1, "Conducted noise immunity." Specified voltage tolerance includes ripple, noise, and
transient response.
transient response.
[6]
Operating condition is defined as random 8 block reads at 330 I/Os per second for ST3450856SS and
347 I/Os per second for ST3300656SS and ST3146356SS models. Current and power specified at nomi-
nal voltages.
347 I/Os per second for ST3300656SS and ST3146356SS models. Current and power specified at nomi-
nal voltages.
[7]
During idle, the drive heads are relocated every 60 seconds to a random location within the band from
three-quarters to maximum track.
three-quarters to maximum track.
General DC power requirement notes.
1.
Minimum current loading for each supply voltage is not less than 1.7% of the maximum operating current
shown.
shown.
2.
The +5V and +12V supplies should 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
starting current must be available to each device.
drive power requirements should be noted. Where multiple units are powered on simultaneously, the peak
starting 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.
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.
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.
and down.
6.2.3
Current profiles
The +12V and +5V current profiles for ST3450856SS, ST3300656SS and ST3146356SS models are shown
below in the following figures.
below in the following figures.
+5V
=
250 mV pp from 0 to 100 kHz to 20 MHz.
+12V =
800 mV pp from 100 Hz to 8 KHz.
450 mV pp from 8 KHz to 20 KHz.
250 mV pp from 20 KHz to 5 MHz.