About ADC input impedance of i.MX25

[yuuki]

Dear all,

Would you teach the input impedance value for ADC ports of i.MX253?
(Max value and Min value)

We investigate the output resistance value of the external device connected to ADC port.
We investigate a measurement error when we changed the output resistance from 10 Ω to 100kΩ.

Best Regards,
Yuuki

[art · Accepted solution]

Actually, the input impedance of the i.MX25 ADC is not strictly specified. However, it is specified in the i.MX25 Data Sheet that the output impedance of a signal source to measure with this ADC must not exceed 1500 Ohm to guarantee the specified measurement accuracy of +/- 0.75 LSB DNL and +/- 2.0 LSB INL.

Have a great day,
Artur

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[yuuki]

Dear Artur-san,

Thank you for your support.

I think that the Max 1500Ohm is specification for Touchscreen.

Do INAUX0:2 pins have specification same as this, too?

Best Regards,

Yuuki

[art]

Yes, all of the ADC inputs of i.MX25 have the same specifications.

Have a great day,
Artur

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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