Seagate Cheetah 15K.4 SAS, Product Manual

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Cheetah 15K.4 SAS Product Manual, Rev. B 27
[4] This condition occurs after OOB and Speed Negotiation completes but before the drive has received the
Notify Spinup primitive.
[5] See paragraph 6.2.1, "Conducted noise immunity." Specified voltage tolerance includes ripple, noise, and
transient response.
[6] Operating condition is defined as random 8 block reads with 225 I/Os per second for ST3146854SS
drives, 230 I/Os per second for ST373454SS drives, and 230 I/Os per second for ST336754SS drives.
Current and power specified at nominal voltages. Decr5 volt supply by 5% increases 5 volt cur-
rent by
2.5%. Decr12 volt supply by 5% increases 12 volt current by 3.0% for ST3146854SS
models, 2.0% for ST373454SS models, and 2.0% for ST336754SS models.
[7] During idle, the drive heads are relocated every 60 seconds to a random location within the band from
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.
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.
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.
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
The +12V and +5V current profiles for ST3146854SS, ST373454SS and ST336754SS models are shown
below in the following figures.
Note: All times and currents are typical. See Tables 2 and 3 for maximum current requirements.
+5V +12V
0 to 100 kHz 150mV 150mV
100 kHz to 10 MHz 100mV 100mV