Seagate ST9120821AS manual Conducted noise, Voltage tolerance, Power-management modes, Active mode

2.9.3Conducted noise

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

Using 5-volt power, the drive is expected to operate with a maximum of 100 mV peak-to-peak square-wave injected noise at up to 10 MHz.

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

2.9.4Voltage tolerance

Voltage tolerance (including noise):

5V ± 5%

2.9.5Power-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:

Table 4:	Power management modes
Power modes		Heads	Spindle	Buffer
Active (operating)		Tracking	Rotating	Full power
Idle, performance		Tracking	Rotating	Self refresh—low power
Idle, active		Floating	Rotating	Self refresh—low power
Idle, low power		Parked	Rotating	Self refresh—low power
Standby		Parked	Stopped	Self refresh—low power
Sleep		Parked	Stopped	Self refresh—low power

•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 disc 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 in Self Refresh Low Power mode, the heads are parked and the spindle is at rest. The drive accepts all commands and returns to Active mode any time disc 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 in Self Refresh Low Power mode, 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 translation parameters intact.

10 Momentus 5400.2 SATA Product Manual, Rev. C