I have design a board using an ADC AD9629, combined with a differential amplifier ADA4940.
It works fine in normal mode. In normal mode I m measuring single pulses from 0V to 6V to VIN without any issue at 10Msps.
I have used an external reference ADR130BUJZ, in order to compensate the temperature variation of my system.
I have an additionnal DAC (MAX5815) which goes to VIN. This DAC apply a DC signal to VIN. With this DAC, I can create a lookup table (in my software) to compensate the gain error.
However, am seeing something odd: Whenever i change the DAC value with the ADC clock ON, my external VREF goes from 1V to 0V. Then the Adc is blocked, I have got to unplug my board.
What can create this issue?