Hello
I am using the ADS5485 ADC in a system. According to the datasheet, the maximum analog input signal to GND is (–0.3 to (AVDD5 + 0.3)). I assume that this is where the protection diodes become forward biased and start conducting.
In normal operation, the analog input level to the ADS5485 ADC will be far less than this. However, our system needs to be able to handle the occasional 'fault' condition where the magnitude of the analog input could exceed (AVDD5 + 0.3). The system must be able to survive these fault conditions and the ADC should not be damaged as a result.
If possible, I would like to find out if there is a specification for the maximum rated current that the protection diodes can safely handle. I am hoping that I would be able to use this to set the source impedance of the ADC driver so that if a fault occurs and the protection diodes start conducting, that the maximum rated current is not exceeded.
The fault condition would be for an 'AC' input. The sample clock frequency is 80MHz and the I/F frequency is 60MHz.
Thanks