Understanding datasheet re analog inputs

Discussion in 'The Projects Forum' started by ebeowulf17, Feb 7, 2015.

  1. ebeowulf17

    Thread Starter Active Member

    Aug 12, 2014
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    Is the maximum input voltage to an ADC dependant on its analog reference?

    I'd like to use an Arduino with AREF set to around 2V so I can get the most precision possible when reading a 1.25-2V signal. The Arduino is running on 5V, so I know the input can't exceed 5.5V. I just wanted to make sure that the limit doesn't drop if the AREF is lowered. I only need good readings up to 2V, but the signal might exceed 2V sometimes.

    I've tried to read the relevant sections of the datasheet, and it looks to me like it's fine, but I'm not sure and I don't want to smoke any more chips this week (embarrassing story!)
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    The cathode of the upper input protection diode on any input pin (including the analog ones) is returned to Vdd, so you should be just fine.
     
  3. ebeowulf17

    Thread Starter Active Member

    Aug 12, 2014
    678
    79
    Sweet, thanks!
     
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