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Allowed Voltages on A/D Converter pins?

Question asked by Laartoor on May 12, 2014
Latest reply on May 15, 2014 by Laartoor

I am a bit confused about the allowed voltages on the ADC pins of the Kinetis K.

a) In section 4 of the data sheets, we have the pin ratings: Vdio is defined as -0.3 to 5.5 volt, and Vaio as -0.3 to Vdd+0.3 volt, where Vaio is for the pure analog pins and Vdio for mixed pins.

b) In section 6 we have the ADC spec, and it states that Vadin must be between Vref low and Vref high.

When I now have a voltage on a pin that satisfies a), but falls outside b), what will happen:

- may I have the pin connected to an analog function, even it if falls outside Vaio?

- may I start an A/D conversion?

The reference manual already tells me that the ADC will clamp values outside Vref low and Vref high to the lowest/highest possible conversion result.