Hello Robert Czech, Thank you for the query. Can you confirm if this is a custom board. [quote userid="502972" url="~/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1500190/am2434-am24x-adc0-measurement-at-ain7"]We disconnected the real signal source and just left a 820 Ohm resistor attached from the AIN7 to GND. With this setup the offset still exists. After we shorted the resistor, the ADC really measured 0mV.[/quote] The input leakage should be less than 10uA. So they should not be measuring 15mv when connecting the input to VSS via a 820 ohm resistor. The most they should measure would be V = I * R = 10uA * 820 ohms = 8.2mV, when we assume the worst case input leakage of 10uA is flowing through the 820 ohm resistor. Does the offset increase if the 820R is increased to 1.5K or 2K. Here are some thoughts I suspect this is being caused by something else. Can you confirm the ADC clock rate. The ADC should be operating at 60MHz. How are the VDDA_ADC0, ADC0_VREFN, and ADC0_VREFP pins connected? Are you able to share the schematics for a quick check. Regards, Sreenivasa
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