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VSC7173

Data Sheet

Revision 4.1

May 23, 2005

Confidential

High-Speed Inputs

The high-speed input receivers are designed to achieve Serial ATA 1.0 compliance using AC-coupling as described in

the Serial ATA 1.0 specification. Recommended input AC-coupling capacitor values are 0.01

µF. The high-speed

input receiver contains an OOB signal detector as shown in Figure 6.

OOB Transfer

The VSC7173 cleanly transfers OOB signals from high-speed inputs to outputs. Two status outputs, OOBPORT0 and

OOBPORT1, indicate whether the input signal is data or a common-mode state. OOBPORT1 and OOBPORT1

correspond to port 0 and port 1, respectively. An OOB detector monitors the amplitude of an incoming signal in

parallel with each high-speed input. When the amplitude is less than the OOB threshold, the OOB status output is

driven HIGH. When the incoming amplitude is greater than the OOB threshold, the OOB status output is driven

LOW.

Setting the OOBSEL1 and OOBSEL0 inputs as shown in the following table configures the OOB threshold level for

all three ports.

NOTE:

All values are differential peak-to-peak voltages.

Figure 5. Pre-Emphasis Diagram

Figure 6. High-Speed Input Receiver

Table 5. Setting the OOB Threshold Level

OOBSEL1

OOBSEL0

OOB THRESHOLD LEVEL

1

0

Nominal setting (150 mV to 250 mV)

0

0

Decrease by ~40 mV

0

1

Decrease by ~80 mV

1

1

Increase by ~40 mV

0

0

1

1

1

1

1

0

1

0

Pre-Emphasis Disabled

0

0

1

1

1

1

1

0

1

0

Pre-Emphasis Enabled

Input

InputN

Input Receiver

OOB Detector

OOB Status

(OOBPORTx signal)

Data

OOBSEL0

OOBSEL1