Hello Philipp,
The TUE values exposed in the Example of 12 bit mode, are the consequence of not calibrate the ADC Module in the worst case.
In order to calibrate it, the ADC contains a self-calibration function that is required to achieve the specified accuracy.
Once calibrated, the TUE can be highly improved and it can be reduced until +-2.
Please find more information about the ADC Calibration function in section 30.4.6, page 628, from the Reference Manual in the following link:
http://www.freescale.com/files/microcontrollers/doc/ref_manual/K02P64M100SFARM.pdf
To complete calibration, you must generate the gain calibration values using the procedure mentioned in the document.
Unfortunately, the minimum average of samples in 16-bit single-ended mode is 4 as is shown in following figure:
Hope this information will be useful for you.
Have a great day.
Best Regards,
David Diaz.
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