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ESP32-S3 RTC IO input current

Posted: Mon Nov 11, 2024 3:38 pm
by Baoshi
In a low power design I'm putting esp32-s3 in deep sleep and use ext1 io to wake up.

Since the wakeup source is a rotary encoder without dent I can't assume it will stop at open position, so I'd prefer a large pull-up resistor to save power if the wiper stops at close position.

The ESP32-S3 datasheet said high-level input current is maximum 50nA. But I use 3.3V source and feed into IO pin through a 1MEG resistor I get 3.0V at the IO pin, meaning 0.3V across 1MEG resistor that works to be 300nA.

Is there a different input current w.r.t RTC IO?

TIA

Re: ESP32-S3 RTC IO input current

Posted: Mon Nov 11, 2024 8:34 pm
by mgsecord62
If your input impedance on the meter you are using to measure the 3 volts is 10 MEG that is what the current draw calculates to be (3.3/11Meg). 10 Meg is pretty typical input impedance for DMMs.

Re: ESP32-S3 RTC IO input current

Posted: Mon Nov 11, 2024 10:57 pm
by Baoshi
Thanks you're right. I need to manually set my DMM input impedance to 10Gohm to get correct result.