Question about Tramp of Vccaux in using EP4SE230F29I4N.
We meet some problems as the following when we use the device of EP4SE230F29I4N in Stratix IV series.
FPGA works normally after welding. However,after about half a year, fpga cannot be loaded at the temperature of -40℃ while it is normal at the normal temperature. The failures are: nCONFIG is in constantly-high level, nStatus and CONFIG_DONE are in constantly-low level, both power supply voltage and time sequence are normal. Delaying the Tramp time of Vccaux which is about 4us when in failure can make fpga work in normal. The Tramp time when in normal temperature is the same with the time when in low temperrature. The following is our application: https://www.alteraforum.com/forum/b4a8cbc5-d925-4124-a44a-37ed271058dc 1.Would you answer us the reason of the above failure and how to solve it? 2.As for time, why does fpga work normally just after welding in normal and low temperature while it trun to failure in low temperature after using ofr a period of time? 3.As for temperature, why can fpga be loaded in the normal temperature when Tramp time is 4us while cannot be loaded normally at the temperature of -40℃?