Cyclone IV PLL lock range: datasheet vs measurement

Hi FvM,

Here is the discussion: showthread.php?t=138. I originally wanted to insert a link, but I was not allowed to do so, as I am still a Beginner!

According to this rule, you will see that Fpfd(min) is lower (x10 factor) than the specified's, too.

I could undertand a difference by a x10 factor between the specified and measured frequencies, taking into account the PVT variations , as you stated.

But a x1000 factor regarding Fvco(min), I cannot. Moreover, that:

- the output clock is really stable (frequency, duty cycle, edges, etc...);

- the measured Fvco(max) corresponds to the specified's.

-> Is the Fvco formula right?

-> Does the lock generation logic take Fvco(min) into account?

-> Any further idea?

Thank you for your collaboration!

Regards,

DEx.