ESP32 Forum

To use ADC attenuation I need to buffer the pins with voltage dividers. To minimise battery power and use highest resistances what is the minimum input current for an ESP32 analog input pin?

ADC input current will be neglible. However, to get the most accurate results from a high impedance source (like a high value voltage divider) you can add a small buffer capacitor (approx 100nF) between the ADC pin and ground.

Excellent, thanks

ESP_Angus wrote: ↑

Mon Feb 19, 2018 6:22 am

ADC input current will be neglible. However, to get the most accurate results from a high impedance source (like a high value voltage divider) you can add a small buffer capacitor (approx 100nF) between the ADC pin and ground.

I have a similar problem, but not for ADC.
I need to detect the generation of very small current, through the transistor and optocoupler to form a simple detection circuit, output about 2uA logic level. Can ESP32 be confirmed with such a low current?

mura_lb wrote: ↑

Fri Oct 11, 2024 8:50 am

I have a similar problem, but not for ADC.
I need to detect the generation of very small current, through the transistor and optocoupler to form a simple detection circuit, output about 2uA logic level. Can ESP32 be confirmed with such a low current?

Datasheet says input leakage is 50nA max, which is an order of magnitude smaller than the 2uA you have, so it should work.