XRK32308_07 Datasheet, PDF(3/16 Page) Exar Corporation

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XRK32308_07 Datasheet, PDF (3/16 Pages) Exar Corporation – 3.3V ZERO DELAY BUFFER

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REV. P1.0.3

PRELIMINARY

XRK32308

3.3V ZERO DELAY BUFFER

DEVICE

XRK32308-1

XRK32308-1H

XRK32308-2

XRK32308-3

XRK32308-4

XRK32308-5H

TABLE 3: AVAILABLE XRK32308 CONFIGURATIONS

FEEDBACK FROM

BANK A FREQUENCY

BANK B FREQUENCY

Bank A or Bank B

Reference

Bank A or Bank B

Reference

Bank A

Reference

Reference/2

Bank B

2 X Reference

Reference

Bank A

2 X Reference

Reference or Reference[5]

Bank B

4 X Reference

2 X Reference

Bank A or Bank B

2 X Reference

Bank A or Bank B

Reference/2

NOTES:

5. Output phase is indeterminant (0Â° or 180Â° from input clock). If phase integrity is required, use the XRK32308â2.

ZERO DELAY AND SKEW CONTROL

FIGURE 2. REF INPUT TO QAX/QBX DELAY VS DIFFERENCE IN LOADING BETWEEN FB AND QAX/QBX PINS

1500

1000

500

-30

-25

-20

-15

-10

-5

-500

-1000

-1500

Output Load Difference: FB Load - QAx/QBx Load (pF)

Note: Target only, actual characterization curve may be slightly different.

To close the feedback loop of the XRK32308, the FB pin can be driven from any of the eight available output

pins. The output driving the FB pin will be driving a total load of 7 pF plus any additional load that it drives. The

relative loading of this output (with respect to the remaining outputs) can adjust the input-output delay. This is

shown in the graph above.

For applications requiring zero input-output delay, all outputs including the one providing feedback should be

equally loaded. If input-output delay adjustments are required, use the above graph to calculate loading

differences between the feedback output and remaining outputs.

For zero output-output skew, be sure to load outputs equally.

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