TM4C1294KCPDT: I do not know the resistance of the internal circuit leading to the ADC input pin.

Hi,

I am an engineer designing medical hardware.

I have a question about the ADC pin of your product "TM4C1294KCPDT".

We have conducted actual measurements of the circuit under the following conditions, but the results were not as expected.

・Input voltage +3.0V

・Rs = 1.8kΩ

▸Results considered to be expected

・Input impedance RADC: 2.5kΩ, so the input power supply 3.0V causes a voltage drop and the input voltage is about 1.9V.

▸Measured results

・No voltage drop occurred and 3.0V was output.

We would like to know the cause of the above result.