Seagate ST336807FC General DC power requirement notes, Conducted noise immunity, Power sequencing

[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 at 254 I/Os per second.

Current and power specified at nominal voltages. Decreasing +5 volt supply by 5% increases 5 volt cur- rent by <0.5%. Decreasing +12 volt supply by 5% increases 12 volt current by 1.4%.

[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 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 con- nector.

+5	V	=	250 mV pp from 100 Hz 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.

26 Cheetah 10K.7 36GB FC Product Manual, Rev. A