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CN-0282 mis-match the timing specification between ADV7611 and ADV7125

Question asked by ysuzuki on Feb 12, 2015
Latest reply on Feb 19, 2015 by ysuzuki

Hello,

 

I have a question about ADV7125 timing specification.

 

CFTL CN-0282 is indicated as a reference circuit for "DVI/HDMI to VGA Converter".

In this circuit, ADV7611 and ADV7125 are used.

But the timing specification is not match between ADV7611 and ADV7125.

 

1. Setup/Hold time of ADV7611 digital output data is indicated in table22 of datadsheet(Rev.D)

 

   End of valid data to negative clock edge : t11 = 1.0ns(typ), 2.2ns(max)

    ("Setup Time" is a little shorter than above because t11 include a time from the end of valid data to cross point.)

 

   Negative clock edge to start of valid data : t12 = 0.0ns(typ, 0.3ns(max)

    ("Hold Time" is a little shorter than above because t12 include a time from the cross point to valid next data.)

 

 

2. Setup/Hold time of ADV7125 digital input is indicated in table-4 of datasheet(Rev.C)

 

   Data and Control Setup : t1 = 0.2ns(min)

   Data and Control Hold  : t2 = 1.5ns(min)

 

Then,

   t11(setup time of ADV7611) > t1(setup time of AVD7125)

   t12(hold time of ADV7611) < t2(hold time of ADV7125) - - - (1)

 

This relation(1) seems make a problem.

 

How should I understand this mis-match ?

 

 

 

Best regards,

ysuzuki

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