Seagate ST3600957SS, 100516226 manual Differential signals, G Bps, SAS-2 SPECIFICATION COMPLIANCE

Table 15 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

11.5.2 Differential signals

The drive SAS differential signals comply with the intra-enclosure (internal connector) requirements of the SAS standard. Table 16 defines the general interface characteristics.

Table 16 General interface characteristics

CHARACTERISTIC	UNITS	1.5 GBPS	3.0 GBPS	6.0 GBPS
Bit rate (nominal)	Mbaud	1,500	3,000	6,000
Unit interval (UI)(nominal)	ps	666.6	333.3	166.6
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

11.6SAS-2 SPECIFICATION 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 6 Gbps 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.

11.7ADDITIONAL INFORMATION

Please contact your 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.

CHEETAH 15K.7 SAS PRODUCT MANUAL, REV. F 52