Teensy 4.1 Analog Inputs

[bdoan]

I am needing to read voltages that may exceed the 3.3V max limit of the 4.1 inputs.

I can certainly divide down the input voltage but I am also needing to limit the loading of the measured source to 10s of microamps.

What is the impressed input impedance of the analog inputs?

Do I need to buffer these inputs?

 

[BriComp]

I believe the analogue inputs expect a low impedance source.
Buffering with an op-amp circuit could provide the step down and low impedance requirement.

 

[bdoan]

I believe the analogue inputs expect a low impedance source.
Buffering with an op-amp circuit could provide the step down and low impedance requirement.

Since the time I posted this question, I tried a resistive divider Vtest->100k->ADC->100k->Gnd

The readings are still accurate