About ADC input impedance of i.MX25

cancel
Showing results for 
Search instead for 
Did you mean: 

About ADC input impedance of i.MX25

Jump to solution
570 Views
yuuki
Contributor V

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

Labels (1)
Tags (3)
0 Kudos
1 Solution
238 Views
art
NXP TechSupport
NXP TechSupport

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

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

View solution in original post

0 Kudos
3 Replies
239 Views
art
NXP TechSupport
NXP TechSupport

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

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

View solution in original post

0 Kudos
238 Views
yuuki
Contributor V

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

0 Kudos
238 Views
art
NXP TechSupport
NXP TechSupport

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


Have a great day,
Artur

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