What is the voltage limits on iMX28 LRADC2...5?

[s_querin]

Hi all,

I'm design a board using the iMX28 and I need to read 4 analog values in the range from 0 to 3.3 voltage and I would use the LRADC2..5 channels for this scope.

In the RM is write:
"For input channels (other than BATT, 5V, or VDDIO) with signals larger than 1.85 V,

the divide-by-two option should be set (HW_LRADC_CTRL2_DIVIDE_BY_TWO).

With the DIVIDE_BY_TWO option set, the maximum input voltage is VDDIO – 50mv."

but in the data sheet I the chapter 3.5.1.1 LRADC Electrical Specifications I read:

"DC input voltage 0-1.85 V"

Is it possible to apply an analog signal in the range from 0 to 3.3 voltage to the LRADC2...5 pins?

Regards
Stefano

[s_querin]

Hi Igor,
thank you for your quick answer.

Best regards

Stefano

[igorpadykov · Accepted solution]

Hi Stefano

RM is correct:

"For input channels (other than BATT, 5V, or VDDIO) with signals larger than 1.85 V,

the divide-by-two option should be set (HW_LRADC_CTRL2_DIVIDE_BY_TWO).

With the DIVIDE_BY_TWO option set, the maximum input voltage is VDDIO – 50mv."

So it is possible to apply an analog signal in the range from 0 to 3.3 voltage to the LRADC2...5 pins

Best regards

igor

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