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ADC Conversion results not accurate

Question asked by Prasanna Naik on Oct 16, 2019
Latest reply on Oct 17, 2019 by Jing Pan

Hi,

I am trying to sample 3 ADC channels (SE8, SE9, SE15) with sampling frequency 1.6KHz. I have connected a bypass capacitor of 0.1uF on each ADC pin. I am not able to achieve accurate ADC conversion results with DC voltage at ADC input pins. There’s a considerable difference between the expected conversion value and actual conversion result. Also the difference is more for higher DC input voltage on ADC pins.

I have attached the test results for reference.

Development Board used: FRDM K22F

ADC configuration:

Clock used: BUS clock (frequency 60MHz)
Clock Divider: Divided by 4

ADC Calibration: Auto calibrated

Long sampling: Disabled

Continuous conversion: Disabled

 

Please help in resolving the issue.

 

Thanks and Best Regards,

Prasanna

 

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