The ADC conversion result is different

[alanyang]

Customer found the ADC conversion result of the same voltage is different within the temperature range from -25C to 125C. Is it right ? There is no spec in the datasheet talking about the deviation percent through all the temperature range ?

[iggi]

Hi Alan,

What MCU does your customer use?
Can you share the test results (temperature points where ADC result differs)?
There was a customer case in the past on a S12G device where at room temperature the absolute error was in specified range and at 120°C it was far more. But, we don't think this is the problem with MCU itself as the ADC conversion performance of a device is tested over whole temperature range. The main factor influencing ADC performance is reference voltage VRH and VRL. Other factors influencing accuracy are source resistance, source capacitance and current injection (assuming the ADC differential reference voltage is stable). That is described in the device reference manual.

Regards,

iggi