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Observer
Observer
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Registered: ‎01-17-2018

Ultrascale kintex MGTREFCLK voltage

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I have an UltraScale XCKU040 device (on the KCU105 eval board). I want to inject an external clock signal into the Kintex pins: MGTREFCLK0N , MGTREFCLK0P, and in my Kintex design they go to a ibufds_gte3.

What electrical level should i inject ?

On ds892 I find:   VMGTREFCLK GTH and GTY transceiver reference clocks absolute input voltage Min = –0.500 V ; Max = 1.320 V.   These are the Absolute Maximum Ratings, but i also want to find out the recommended operating conditions

On ug576  Figure 5-4 illustrates the differential clock input voltage swing, peak-to-peak, which is defined as MGTREFCLKP – MGTREFCLKN.  This is called VIDIFF in the figure.

On ds892  Table 49: GTH Transceiver Clock DC Input Level Specification;   VIDIFF min= 250 ; Max= 2000 mV.

This is strange: the Absolute Maximum Ratings have Min = –0.500 V ; Max = 1.320 V; so Max - Min = 1.820 V; but  the Input Level Specification has Max VIDIFF= 2000 mV which is bigger than the Absolute Maximum Ratings !!

Please help.

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Observer
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Registered: ‎01-17-2018
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Registered: ‎01-17-2018
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