ADC Troubleshooting

Sample Offset

Phenomenon	Sample offset
Cause	Calibration parameters are not applicable. Mismatched input impedance.
Solution	Calibrate again. Adjust the input impedance, making sure internal resistance of the signal source is much lower than that of ADC.

Note

• Calibrate the whole application circuit together if possible.

• Refer to the hardware design specification to obtain ADC internal impedance.

Channel Interference

Phenomenon	Channel interference
Cause	Mismatched input impedance leads to poor driving capability of input source. Too high sample frequency.
Solution	Reduce the internal resistance of the signal source. Reduce sample frequency.

Sampling Voltage Interference

Phenomenon	Sampling voltage interference, Low SNR
Cause	Unreasonable PCB layout
Solution	Check PCB layout, such as location of power supplies and high-speed signals, etc. Taking mean value of multi-point samples is suggested.