DS22EV5110

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SNLS311D – APRIL 2009 – REVISED FEBRUARY 2010

OUTPUT DE-EMPHASIS

De-emphasis is the conditioning function for use in compensating against backplane and cable transmission loss.

The DS22EV5110 provides four steps of de-emphasis ranging from 0, 3, 6 and 9 dB, user-selectable dependent

on the loss profile of output channels. Table 3 shows the De-emphasis control with default VO = 1000 mVp-p,

and Figure 7 shows a driver de-emphasis waveform.

OUTPUT VO CONTROL

Output differential voltage (VO) is controlled through VOD_CRL pin ties an external resistor to the ground as

shown in Table 4. Users should restrict the external resistor values used to be 12 k

Ω to 24 kΩ. +5% tolerance is

recommended.

Table 2. Equalization Control

INPUTS

RESULT

EQ2

EQ1

EQ0

Equalization in dB (1.125 GHz)

0

0

0

0 (default)

0

0

1

12

0

1

0

18

0

1

1

21

1

0

0

24

1

0

1

26

1

1

0

28

1

1

1

30

Table 3. De-Emphasis Control

INPUTS

RESULT

VO De-Emphasis level in mVp-p

DE1

DE0

VO De-Emphasis in dB

(VODE w/VOD_CRL = 24 k

Ω

0

0

1000 (default)

0 (default)

0

1

710

-3

1

0

500

-6

1

1

355

-9

Table 4. VO Control

External Resistor Value

Applications

VO Level (mVp-p)

(VOD_CRL pin)

24 k

Ω

DC Coupled

1000

12 k

Ω

AC Coupled

1000

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