If my AD-converter above is set to work within let's say 0-2 V, what happens with the output signal (10 bits) if the input signal goes under 0 V or over 2 V? I couldn't find it in the data sheet. I guess the converted data is invalid in some way, but how long does it take to get back to normal function? I mean, let's say I have a glitch that goes under 0 V for a short period, is the data that follows (when input is normal) valid or invalid?
Exceeding the input range of the AD7778 to within the absolute max limits of the part...which are specified as -0.3V to Vcc+0.3V will cause the o/p code to sit at either +ve or -ve full-scale. The input track and hold amplifier may saturate, however once the i/p voltage returns to within the normal operating range, the track and hold amp will acquire the new voltage in a time specified as the acquisition time..see page 2 of the datasheet. Exceeding the max ratings of the ADC, may cause permanent damage to the device, and if there is a possibility of this occuring, then the device should be protected against this occurance. One such method is to connect shottky diodes between the input pin and the supplies, such that in the event of an overvoltage occurance, the input voltage is clampled to 0.3V outside the supplies. A series resistor should be included to limit the current in this condition.