GS3490

Final Data Sheet

Rev. 1

GENDOC-058568

April 2014

16 of 22

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Automatic muting of the output can be enabled by connecting the CD pin to the

EQ_OP_CTL pin.

If the connection is made directly, as shown in Figure 4-3, the output would be in its

Figure 4-3: Direct Loopback

4.2 Cable Driver Mode

4.2.1 Cable Driver Mode Enable

To enable Cable Driver Mode, EQ_DISABLE and CD_ENABLE must be set to logic HIGH.

These two pins may be tied together and controlled from a single logic signal.

4.2.2 Differential Digital Data Inputs (DDI/DDI)

The GS3490 features a differential input buffer (DDI/DDI) with on-chip 100

Ω differential

termination.

The differential data input signal is connected to the DDI and DDI input pins of the

device.

The serial data input buffer is capable of operation with any binary coded signal that

meets the input signal level requirements, in the range of 270Mb/s to 2.97Gb/s in Cable

Driver Mode. The input circuit is self-biasing to allow for simple AC or DC-coupling of

input signals to the device.

4.2.3 Serial Data Outputs (SDO/SDO)

The GS3490 features a current-mode differential output driver capable of achieving

commonly used output swing configurations, please refer to Section 4.2.5.

The SDO/SDO pins of the device provide the serial data outputs.

Please refer to Section 5.1 for the correct way to implement the bi-directional serial

input/output. Other application circuits are not supported.