ADC reference voltage accuracy / tolerance

[bjalgera]

My understanding is that the ADC reference voltage is 1.1V and that different input ranges can be achieved via software settable "attenuation" settings.
My question is about the accuracy and tolerance of the reference itself. 5%? 1%? drift over temperature?

Thanks!

[loboris]

It is nowhere documented (I couldn't find it), but the reference voltage source should be an bandgap reference with at least 50 ppm/°C to be usable...

[WiFive]

https://esp32.com/viewtopic.php?f=12&t= ... 351#p11351