Hi Nagesh,
thank you for your reply. Taking in account point 1 and 2 the linearity is ok. I am aware of the DDC264 and I am already using the evaluation board; only problem is that we do not have a facility to do assebly of the board and since the DDC264 cannot be hand solded we use the AFE until we can acces to a pick and place. Anyway, our application is suppost to measure charge packets, the linearity I was doing it is just a characterization of our data acquisition system.
Regarding the failure, I am sure I didn't exceed neither the Abs max ratings nor 10mA per pin but the chip I was testing doesn't work anymore: EOC is always low, the voltage at the input pin is about 0.1V and the output is stuck. Maybe it was just a weak component...
Thanks anyway,
best regards
Iolanda