Does anyone have knowledge or experience on what type of voltage and durations the FPGA can survive or not survive to the Vccint. Also, does anyone have a simulation model of how the Vccint behaves for an FPGA. I am interested in understanding how much energy/power would destroy an FPGA and how long does it need to be applied.
OK. Go look at the datasheet for a device in the technology node you are interested in (e.g. 7-series).
In TABLE 1, on the first page, you find the absolute maximum specifications.
Stay at, or below these, for any length of time, and NO DAMAGE RESULTS.
Go above these values, for any amount of time, and ALL BETS ARE OFF, and you may have damaged the device.
Go well beyond any of these values for a more reasonable amount of time (minutes to hours) and you are most certainly to have rendered the device useless (basically it becomes a dirty piece of glass for all intents and purposes).
If you are looking for ways to destroy a device, perhaps the fastest is a hammer.
Do not expect to return any device to Xilinx or our authorized distributors for a refund, or for failure analysis. And we thank you for buying those devices (which we will never have to be concerned with ever again).