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 17 for the output characteristics of the LED drive signals.

Table 17:

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 18 defines the general interface characteristics.

Table 18: 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 time limits on the signal at the compliance point. The time values between X1 and (1 - X1) cover all but 10-12of the jitter population. The random content of the total jitter population has a range of ± 7 standard deviations.

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Cheetah T10 SAS Product Manual, Rev. A

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Seagate ST373355SS LED drive signal, Differential signals, General interface characteristics, Eye masks Eye masks overview

ST3300555SS, ST3146755SS, ST373355SS specifications

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