ADC Accuracy issue

[Thiru2483]

Hi,

I am working with S32k144 and S32k322 MCU in the ADC module.

In s32k144 via tigger source with pdb triggering the adc ,  and the result observed to be accuracy issue with 40 count

Similarly s32k322 via BCTU , tigger the adc , count accuracy are expected as per the voltage is feed , so accuracy issue compared to s32k144

What this background calibration tigger unit will do exact , why this issue can not be seen in this?

What exact SAR Ip is used , 

Could you please help me out this , as it makes more issue to conclude the exact difference.

S32K144EVB

[PavelL]

Hello @Thiru2483 ,

Please check this thread Solved: S32K3 Confusion about ADC accuracy and results - NXP Community . The general description of calibrating capacitive SARs can be found in this thread 16-bit SAR ADC calibration - NXP Community .

If you do all necessary steps during ADC initialization - like calibration - the conversion precision is mainly caused by external components (and VREF, of course) - please refer to AN4373, Cookbook for SAR ADC Measurements - Application note (nxp.com) . Necessary information (CS, CP1, CP2, RSW, RAD, ...) to calculate values of external components can be found in MCU's data sheet. 

Best regards,

Pavel