Seagate BARRACUDA XT SERIES SATA ST32000641AS - Manual (Page 15)

Barracuda XT Series SATA Product Manual, Rev. C 9
2.6.2 Conducted noise
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.
2.6.3 Voltage tolerance
Voltage tolerance (including noise):
5V + 10%
12V + 10 %
2.6.4 Power management modes
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.
• Idle mode
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.
• Sleep mode
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.
• Idle and Standby timers
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.
Power modes Heads Spindle Buffer
Active Tracking Rotating Enabled
Idle Tracking Rotating Enabled
Standby Parked Stopped Enabled
Sleep Parked Stopped Disabled