How much current can I draw from VADC pin?

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1

Hi, I need to connect 12 potentiometers to the adc inputs in the BBB (through an analog multiplexer). I have found that if I use potentiometers with lower resistance values (2Kohm), the input is less noisy than if I use higher resistance pots (500KOhms). Since the pots are “powered” by VADC and AGND (1.8Volts), I need to know how much current I can draw from these two pins.
Anyone? :slight_smile:

2

I'm not sure. I read somewhere that the internal reference really should not supply current, but looking at the schematic, it looks like it's powered from the VDD_1V8 1.8 V rail, which can supply a total of 400 mA (according to the SRM). I don't know how much the rest of the system draws.

I have a 5K and 10K pot on mine, seems to work, but in the next version I will put a voltage follower on it.

3

It is for reference only. if you need power, supply a regulator for that
purpose.

4

It is for reference only. if you need power, supply a regulator for that
purpose.

5

Thanks!