11.5.2 Differential Signals; Sas-2 Specification Compliance; Additional Information - Seagate ST1200MM0007 Product Manual

The Ready LED Out signal is designed to pull down the cathode of an LED. The anode is attached to the proper +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.
Table 12 LED drive signal
State
LED off, high
LED on, low

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
Table 13 General interface characteristics
Characteristic
Bit rate (nominal)
Unit interval (UI)(nominal)
Impedance (nominal, differential )
Transmitter transients, maximum
Receiver transients, maximum
11.6 SAS-2 S
PECIFICATION COMPLIANCE
Seagate SAS-2 drives are entirely compatible with the latest SAS-2 Specification (T10/1760-D) Revision 16.
The most important characteristic of the SAS-2 drive at 6Gb/s is that the receiver is capable of adapting the equalizer to
optimize the receive margins. The SAS-2 drive has two types of equalizers:
1. A Decision Feedback Equalizer (DFE) which utilizes the standard SAS-2 training pattern transmitted during the SNW-3
training gap. The DFE circuit can derive an optimal equalization characteristic to compensate for many of the receive
losses in the system.
2. A Feed Forward Equalizer (FFE) optimized to provide balanced receive margins over a range of channels bounded by
the best and worst case channels as defined by the relevant ANSI standard.
11.7 A
DDITIONAL 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.
S E P
EAGATE NTERPRISE ERFORMANCE
Test condition
£ £
0 V VOH 3.6 V
I = 15 mA
OL
Units
Mbaud
ps
ohm
V
V
10K HDD 7 P
V RODUCT
Output voltage
-100 μA < I < 100 μA
OH
£ £
0 V 0.225 V
OL
1.5Gb/s 3.0Gb/s
1,500 3,000
666.6 333.3
100 100
± 1.2 ± 1.2
± 1.2 ± 1.2
M , R . C
ANUAL EV
6.0Gb/s
6,000
166.6
100
± 1.2
± 1.2
50