Internal RTC clock lag issue

[Freedom_Neo]

I am using below componnet tools

MCU: STM32H7B3IIT6

IDE: STM32CubeIDE Version: 1.9.0

CRYSTAL: RT3215-32.768-12.5-TR ( 32.7680KHZ 12.5PF)

I work with internal RTC. I will use for clock. But RTC clock behinds real clock. While the product is running, the lag increases even more. But when the product is turned off, when it is turned on after 2 days, the rest continues as it was 2 days ago. In other words, I am experiencing the lagging event while the product is running. When the product is turned off, there is no lag.

[waclawek.jan]

The load capacitance given by manufacturer is not equal to capacitance of capacitors you connect. Read AN2867.

JW

[Freedom_Neo]

I read design guide. When we change capacitance is changed power consumption and frequency accuracy. If we want most accuracy, we use high value capacitance(for exp 9, 12pF)

[Peter BENSCH]

@Community member​ please open a new thread for the discussion about the STM32H7B3I-DK, because this is a different topic than the original question.

Regards

/Peter

[Freedom_Neo]

I opened new a thread with this topic

https://community.st.com/s/question/0D53W00001SeBaVSAV/why-do-we-choose-lse-capacitance-low