ESP32-C6 internal 150 vs 32 kHz RC oscillator

[Marius28]

Hello,

in my project the ESP32-C6 is most of the time in deep sleep. Now after 5 days the system clock has deviated by almost 5 minutes.

At the ESP32-C6 System Time documentation i read something about another internal 32 kHz RC oscillator but there is no description only for the default 150 kHz RC oscillator. Will the internal 32 kHz RC oscillator solve this time deviation problem?

I'm missing some technical details for both internal RC oscillator at the docs. For example if i use the internal 32 kHz is there a difference in the deep sleep current?

[ESP_krzychb]

Hello Marius28 ,
Using another RC oscillator will not solve the time deviation problem. You need a more precise clock source.
A typical solution to reduce the time drift in sleep mode is by adding an external RTC clock.

[Marius28]

Hello Marius28 ,
Using another RC oscillator will not solve the time deviation problem. You need a more precise clock source.
A typical solution to reduce the time drift in sleep mode is by adding an external RTC clock.

Thanks, i already thought that i need an external clock source. But why is there a 150 and 32 kHz RC oscillator available?

I checked both internal RC oscillators 150 vs 32 kHz as clock source:
150 kHz: The time deviation was 25 seconds after 10 hours of deep sleep.
32 kHz: The time deviation was 0 second after 14 hours of deep sleep.

So it seems that the 32 kHz RC oscillator is more precise?