Seagate Barracuda ST3160021AS - Manual (Page 18)

10 Barracuda 7200.7 Serial ATA Product Manual, Rev. N
cessful exchange of Out-Of-Band (OOB) signals with a functional host-side Serial ATA port. In desktop
systems, SATA transceivers should initialize OOB as soon as power comes ready to guarantee the drive spins
up quickly. Seagate disc drives will not spin up without an operational host-side Serial ATA transceiver.
Additional details
Upon system power up, PHY communication is initiated with a COMRESET signal, which is generated by the
host-side transceiver. COMRESET is followed by a COMINIT signal generated by the disc drive transceiver.
COMRESET and COMINIT are followed by an exchange of COMWAKE signals and Align primitives. The disc
drive will spin up after the successful exchange of Align primitives cause the PHY to come ready.
For more details, refer to:
• Section 6.8 of the Serial ATA 1.0 High-Speed Serialized AT Attachment specification
• Section 6.2 of the Serial ATA II: Extensions to Serial ATA 1.0 specification
• SATA 1.0 design guides
Note. These specifications and guides are available on the Serial ATA web site (www.serialata.org).
2.8.3 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 voltage by the typical RMS read/write
current.
2.8.4 Voltage tolerance
Voltage tolerance (including noise):
5V ± 5%
12V ± 10%