S32K144 ADC collect is not correct when voltage is below 7V

[547416104]

Hello EveryOne,

 I find the ADC collect result is not correct when battery voltage is below 7V on S32k144 100pin, the test result as below:

7.6V -> 0x288

7.5V -> 0X27B

7.4V -> 0X272

7.3V -> 0X274

7.2V -> 0x275

7.1V -> 0x277

7.0V ->  0x27A

6.9V -> 0x27C

6.8V -> 0x27E

6.7V -> 0x281

6.6V -> 0x283

6.5V -> 0x286

I use SDK to config the ADC module, whether need to do other configure for ADC module, thanks

[Robin_Shen · Accepted solution]

Hi 

Can you introduce the sampling circuit? The VADIN (ADC Input voltage) to S32K1 should be between VREFL - VREFH.
Please check if VREFH changes when the battery voltage drops, and make sure that the ADC input voltage and VREFH do not change.

Best Regards,
Robin
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[547416104]

The issue is fixed, HW engineer check is VREFH voltage is not ok, update the IC, the issue is fixed.