Seagate Enterprise Performance 10K HDD v9 Product Manual, Rev. D (Draft 2)
65
The Ready LED Out signal is designed to pull down the cathode of an LED. The anode is attached to the 3.3 volt supply
through an appropriate current limiting resistor. The LED and the current limiting resistor are external to the drive. See the next table
for the output characteristics of the LED drive signals.
11.5.2 Differential signals
The drive SAS differential signals comply with the intra-enclosure (internal connector) requirements of the SAS standard.
The table below defines the general interface characteristics
11.6
SAS-3 Specification compliance
Seagate SAS-3 compatible drives are compliant with the latest SAS-3 Specification (T10/BSR INCITS 519 rev. 06).
The main difference from SAS-2 is the Tx and Rx training that allows the host and drive to adjust the amplitude and emphasis values
to the channel. The receiver still employs Decision Feedback Equalizer (DFE) and Feed Forward Equalizer (FFE) circuitry to accomplish
this training.
11.7
Additional information
Please contact the Seagate representative for SAS electrical details, if required.
For more information about the Phy, Link, Transport, and Applications layers of the SAS interface, refer to the Seagate
SAS Interface
Manual
, part number 100293071.
For more information about the SCSI commands used by Seagate SAS drives, refer to the Seagate SCSI Commands Reference Manual,
part number 100293068.
Table 19 LED drive signal
State
Test condition
Output voltage
LED off, high
0 V ≤ VOH ≤ 3.6 V
-100 μA < IOH < 100 μA
LED on, low
IOL = 15 mA
0 ≤ VOL ≤ 0.225 V
Table 20 General interface characteristics
Characteristic
Units
3.0Gb/s
6.0Gb/s
12.0Gb/s
Bit rate (nominal)
Mbaud
3,000
6,000
12,000
Unit interval (UI) (nominal)
ps
333.3
166.6
83.3
Impedance (nominal, differential )
ohm
100
100
100
Transmitter transients, maximum
V
± 1.2
± 1.2
± 1.2
Receiver transients, maximum
V
± 1.2
± 1.2
± 1.2
