Input Voltage Requirements - Western Digital Re EX800M Technical Reference Manual

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Table of Contents

Specifications

The drive also supports the SATA power management feature that lowers the average power

consumption of the SATA interface.

2.4.3.2

WD drives additionally support T13 Extended Power Conditions, as stated in the ACS-2 specification.

Power savings features, normally only available in notebook drives, are now included in our Enterprise

products. With these features enabled, drive power can be reduced automatically via inactivity timer, or

manually via Host command. In timer based mode, the drive automatically starts reducing its power

based on inactivity of commands from the Host. With progression into the idle states, the drive saves

more and more power, but consequently takes longer to recover and respond to Host media

commands.

A summary of the new low power modes and what the drive does in each mode is shown below:

Idle_A

Heads Floating Over Disk

<10 ms recovery

Idle_B

Heads Parked

<650 ms recovery

Idle_C

Heads Parked, Reduced RPM

3-15 sec recovery (see the Power Conditions Log for the drives actual recovery time)

Idle_c recovery current limited to the maximum user mode power.

Standby_Y

Heads Parked, Reduced RPM

3-15 sec recovery (see the Power Conditions Log for the drives actual recovery time)

Standby_y recovery can use full spin up power.

Standby_Z

Traditional standby

Drive not spinning

Recovery is similar to a typical TTR (Time To Ready) for the HDD

WD has added the Power Condition Log, which defines the support, enable bits, and timers for all

power conditions. The power management timers start running after all Host commanded drive

activity is complete, and will run during drive background operations, but do not take effect until those

background operations are completed. The timer expiration min/max values are visible to the Host/

Initiator, but are rounded silently by the drive to its internal min/max values. The timer enable and

timer values can be marked independently as changeable. Please note that some Host Operating

Systems may be unable to take advantage of the inactivity timers, as they constantly ping the Drive

with writes to update a time stamp. In these situations it is advisable to extend the Idle_B timer value

beyond the time interval of the writes, or to disable the timer entirely. Please see your WD

representative for help with questions about these features.

2.4.4

The input voltage requirements are +5.0V ± 5% and +12.0V ± 10%.

SATA Extended Power Conditions (EPC)