Question about ADC bandgap voltage value

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Question about ADC bandgap voltage value

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zyt
Contributor II

Hello everyone.

Now I use ADC module of s32k146, and have get adc value of banggap. It's about 0.98v after converter.

In datesheet, the bandgap voltage value is described as below:

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How can I know the precisely bandgap voltage value of my chip? And how to judge there is some error of adc module or the bandgap voltage value is really 0.98V?

Thank you.

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davidtosenovjan
NXP TechSupport
NXP TechSupport

Hi, if you measure 0.98V, it is perfectly within specified range.

Bandgap voltage is fixed voltage reference, more or less independent on reference voltage (imagine Zener diode).

Regarding evaluation of ADC accuracy I would recommend to use different channel (calibrated laboratory voltage source), as here you cannot distinguish between band gap tolerance and ADC error contribution.

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949147417
Contributor I

Hello, what is the ADC count value?  about 819?  thanks

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davidtosenovjan
NXP TechSupport
NXP TechSupport

Hi, if you measure 0.98V, it is perfectly within specified range.

Bandgap voltage is fixed voltage reference, more or less independent on reference voltage (imagine Zener diode).

Regarding evaluation of ADC accuracy I would recommend to use different channel (calibrated laboratory voltage source), as here you cannot distinguish between band gap tolerance and ADC error contribution.