STM32WL DAC Sample-And-Hold: Internal capacitor?

[surumadurum]

I want to generate a constant, steady voltage as COMP INPM in STOP1 with the DAC (using HAL libs at the moment).

Unfortunately I cannot get a steady signal. The voltage drifts around some seconds, stabilises and starts from the beginning (oddly seems to relate to COMP interrupt, but might be coincidence).

I was wondering whether this is possible without an external capacitor? The manual mentions an internal capacitor and gives formulas to calculate the sample, hold&refresh times, but the specs of the internal cap are nowhere stated.

Does this mean, sample and hold without external cap only works with disabled buffer and on-chip peripherals selected only?
What would be the correct values for sample,hold&refresh in this scenario?

 

Thanks,

Robert

[STTwo-32]

Hello @surumadurum 

According to the DS13293, the DAC can't be enabled on STOP 1 mode. It just retain his curent configurations.

Best Regards.

STTwo-32