Doh! My PLLs lose lock. Crosstalk?

Hi Pete,

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I fell across the answer by accident. We drive a 28 bit bus from one side of the chip at 40MHz, so that's a lot of output pins changing at the same time.

So.. I changed the current drive strength on all the outputs (except outgoing clocks and strobes) from 24mA which was the default, to 4mA.

This seems to have fixed it. At last. After three months...

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Thanks for the update.

How 'well' is this fixed though?

Did you try different current strengths? Did you try different combinations of bit patterns, eg. walking 1's, walking 0's, an increasing number of transitions on the bus, a PRBS signal over the bus?

Cheers,

Dave