Conducted Noise Immunity; Power Sequencing - Seagate ST318436LW Product Manual

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[5] See Section 6.2.1 "Conducted Noise Immunity." Specified voltage tolerance is inclusive of ripple, noise,
and transient response.
[6] Operating condition is defined as random 8 block reads at 162 I/Os per second. Current and power speci-
fied at nominal voltages. Decreasing +5 V supply by +5% increases 5 V current by 2.31%.
General Notes from Table 2:
1. Minimum current loading for each supply voltage is not less than 4% of the maximum operating current
shown.
2. The +5 and +12 volt supplies shall 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 start-
ing current must be available to each device.
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 con-
nector.
+5 V = 250 mV pp from 0 to 100 kHz and 100 mV pp from 100 kHz to 10 MHz.
+12 V = 250 mV pp from 0 to 100 kHz and 100 mV pp from 100 kHz to 10 MHz.
6.2.2

Power sequencing

The drive does not require power sequencing. The drive protects against inadvertent writing during power-up
and down. Daisy-chain operation requires that power be maintained on the terminated drive to ensure proper
termination of the peripheral I/O cables. To automatically delay motor start based on the target ID (SCSI ID)
enable the Delay Motor Start option and disable the Enable Motor Start option on the J2 connector. See Sec-
tion 8.1 for pin selection information. To delay the motor until the drive receives a Start Unit command, enable
the Enable Motor Start option on the J2 connector.
Barracuda 18XL Product Manual, Rev. A