Seagate U4 ST36421A - Manual (Page 18)

10 U4 Family Product Manual, Rev. D
1.7.2 Conducted noise
Input noise ripple is measured at the host system power supply across
an equivalent 80-ohm resistive load on the +12 volt line or an equivalent
15-ohm resistive load on the +5 volt line.
• Using 12-volt power, the drive is expected to operate with a maximum
of 120 mV peak-to-peak square-wave injected noise at up to 10 MHz.
• 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 volt-
age by the typical RMS read/write current.
1.7.3 Voltage tolerance
Voltage tolerance (including noise): 5V
±
5% and 12V
±
10%
1.7.4 Power-management modes
The drive provides programmable power management to provide great-
er energy efficiency. In most systems, you can control power manage-
ment 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 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
Power Mode Heads Spindle Buffer
Active Tracking Rotating Enabled
Idle Tracking Rotating Enabled
Standby Parked Stopped Enabled
Sleep Parked Stopped Disabled