Seagate ST32000641AS Barracuda XT Series SATA Product Manual - Page 15

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: Power modes Active Idle Standby Sleep Heads Tracking Tracking Parked Parked Spindle Rotating Rotating Stopped Stopped Buffer Enabled Enabled Enabled 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 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 disabled, 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. • 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 commands and returns to active mode when disk access is necessary. Barracuda XT Series SATA Product Manual, Rev. C 9