Seagate ST36421A, ST32112A, ST38421A Conducted noise, Voltage tolerance, Power-management modes

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:

Power Mode	Heads	Spindle	Buffer
Active	Tracking	Rotating	Enabled
Idle	Tracking	Rotating	Enabled
Standby	Parked	Stopped	Enabled
Sleep	Parked	Stopped	Disabled

•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