Question, i.MX28 LRADC

[Aemj]

Hi Team,

I would like to ask about LRADC of i.MX28.

From the description in i.MX28 datasheet, the power source of LRADC seems to be VDDA. Right?

And the datasheet says that the maximum voltage of LDRADC is 1.85V.

(1)

Is it possible for LRADC to operate correctly for 1.85V input to LRADC, in the situation that VDDA is lower than 1.85V?

(2)

The reference voltage, the internal Bandgap reference, for the ADC is always 1.85V?

Thanks,

Miyamoto

[art · Accepted solution]

Q. From the description in i.MX28 datasheet, the power source of LRADC seems to be VDDA. Right?

A. No, this is not right. The supply voltage for LRADC is fed directly from the Power Supply module, it is derived from either Battery or V4P2 voltage by a linear regulator.

Q. Is it possible for LRADC to operate correctly for 1.85V input to LRADC, in the situation that VDDA is lower than 1.85V?

A. As told before, VDDA does not affect the LRADC operation. So, the answer is: yes, it is possible for LRADC to operate correctly for 1.85V input to LRADC, in the situation that VDDA is lower than 1.85V.

Q. The reference voltage, the internal Bandgap reference, for the ADC is always 1.85V?

A. Yes.

Have a great day,
Artur

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