Seagate ST3146954FC, ST373554FC manual General DC power requirement notes, Conducted noise immunity

and 230 I/Os per second for ST373554FC andST336854FC models. Current and power specified at nom- inal voltages. Decreasing +5 volt supply by 5% increases 5 volt current by 2.5%. Decreasing +12 volt sup- ply by 5% increases 12 volt current by 3.0% (2% for ST373554FC and ST336854FC 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 1.2% 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.

6.2.1Conducted 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.

+5 V	=	250 mV pp from 0 to 100 kHz to 20 MHz.
+12 V	=	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.

6.2.2Power sequencing

The drive does not require power sequencing. The drive protects against inadvertent writing during power-up and down.

6.2.3Current profiles

The +12V and +5V current profiles for the ST3146954FC, ST373554FC, and ST336854FC models are shown below in the following figures.

Note: All times and currents are typical. See Table 2 for maximum current requirements.

Cheetah 15K.4 FC Product Manual, Rev. B 27