has anyone experienced problems when operating Cool Runner (XPLA3) CPLDs near the capacity of their macrocells?
specifically, we have two devices that have failed independently with hard short circuits to ground on the 3.3V power supplies. a third device showed erratic behavior. in all 3 devices, more than 90% of the macrocells are used (and they all have the same program).
ESD has been investigated as a potential cause. however, after a thorough ESD audit, it appears unlikley there was an ESD problem.
i have heard some anecdotal evidence that this can happen when too many of the macrocells are used. has anyone heard of this or seen it documented or reported elsewhere?