Seagate ST32000641AS ユーザーズマニュアル

Barracuda XT Series SATA Product Manual, Rev. C 

  9

Input noise ripple is measured at the host system power supply across an equivalent 80-ohm resistive load on the +12V 
line or an equivalent 15-ohm resistive load on the +5V line.

• Using 12-V power, the drive is expected to operate with a maximum of 120 mV peak-to-peak square-wave injected 

noise at up to 10MHz.

• Using 5-V power, the drive is expected to operate with a maximum of

100 mV peak-to-peak square-wave injected noise 

at up to 10MHz.

Note. Equivalent resistance is calculated by dividing the nominal voltage by the typical RMS read/write current.

Voltage tolerance (including noise):

  5V + 10% 

 

12V + 10 %  

The drive provides programmable power management to provide greater energy efficiency. In most systems, you can 
control power management through the system setup program. The drive features the following power management 
modes:

• Active mode 

The drive is in active mode during the read/write and seek operations.

The buffer remains enabled, and the drive accepts all commands and returns to active mode any time disk access is 
necessary.

• Standby mode 

The drive enters standby mode when the host sends a standby Immediate command. If the host has set the standby 
timer, the drive can also enter standby mode automatically after the drive has been inactive for a specifiable length of 
time. The standby timer delay is established using a standby or idle command. In standby mode, the

 

drive buffer is 

enabled, the heads are parked and the spindle is at rest. The drive accepts all commands and returns to active mode 
any time disk access is necessary.

The drive enters sleep mode after receiving a sleep command from the host. In sleep mode, the drive buffer is dis-
abled, the heads are parked and the spindle is at rest. The drive leaves sleep mode after it receives a hard reset or soft 
reset from the host. After receiving a reset, the drive exits sleep mode and enters standby mode with all current trans-
lation parameters intact.

Each time the drive performs an active function (read, write or seek), the standby timer is reinitialized and begins 
counting down from its specified delay times to zero. If the standby timer reaches zero before any drive activity is 
required, the drive makes a transition to standby mode. In both Idle and standby mode, the drive accepts all com-
mands and returns to active mode when disk access is necessary.

Active

Tracking

Rotating

Enabled

Idle

Tracking

Rotating

Enabled

Standby

Parked Stopped

Enabled

Sleep

Parked

Stopped

Disabled