I'm using 4 ch. of AD7656 in hardware mode. Other 2 ch. are put to gnd. Logic is powered from 5V, analog +15V, -15V. The ADC is working near high voltage switching. I have big problem, the device must operate reliably but unfrontunately it's stops the conversion (do not set the busy signal). Is it a distortion on the reset pin? I have no idea to protect this circuit. After power up microcontroller set CONV A,B,C high, after that RESET high, delay 100ms, RESET low, CONV A,B,C low.