Seagate ST9146802SS LED drive signal, Differential signals, General interface characteristics

Table 24: Ready LED Out conditions

Normal command activity	LED status
Format in progress, each cylinder change	Toggles on/off

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 resis- tor are external to the drive. See Table 25 for the output characteristics of the LED drive signals.

Table 25:	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

9.5.2Differential signals

The drive SAS differential signals comply with the intra-enclosure (internal connector) requirements of the SAS standard.

Table 26 defines the general interface characteristics.

Table 26: General interface characteristics

Characteristic	Units	1.5 Gbps	3.0 Gbps
Bit rate (nominal)	Mbaud	1,500	3,000
Unit interval (UI)(nominal)	ps	666.6	333.3
Impedance (nominal, differential )	ohm	100	100
Transmitter transients, maximum	V	± 1.2	± 1.2
Receiver transients, maximum	V	± 1.2	± 1.2

9.5.2.1Eye masks

9.5.2.1.1Eye masks overview

The eye masks are graphical representations of the voltage and point. The time values between X1 and (1 - X1) cover all but 10-12of the total jitter population has a range of ± 7 standard deviations.

time limits on the signal at the compliance of the jitter population. The random content

Savvio 10K.2 SAS Product Manual, Rev. D 61