STM32L431 DAC

kazuchib · ‎2022-02-10

Which DAC method is used for STM32L431, R-2R or resistor strings?

Different things are written in the two materials.

https://www.st.com/content/ccc/resource/training/technical/product_training/01/4b/81/0e/21/a6/4c/55/STM32L4_Analog_DAC.pdf/files/STM32L4_Analog_DAC.pdf/jcr:content/translations/en.STM32L4_Analog_DAC.pdf#page=4

block diagram

https://www.st.com/resource/en/datasheet/stm32l431cb.pdf#page=39

3.16 Digital to analog converter (DAC)

Peter BENSCH · ‎2022-02-10

Welcome, @kazuchib, to the community!

R-2R networks are also called resistor networks and DACs also like to use this R-2R.

Where do you see a difference?

Regards

/Peter

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kazuchib · ‎2022-02-11

Thank you for your answer

I thought the resistor strings were the method of linking below.

https://www.researchgate.net/figure/Simplest-Voltage-Output-Thermometer-DAC-The-Kelvin-Divider-String-DAC_fig1_266008269

Can you show me the details of the DAC used in the STM32L431?

Peter BENSCH · ‎2022-02-11

May I ask what this information is relevant for?

Background: with the R-2R converter, the binary value is fed in directly and then decoupled with a voltage follower, so that the R-2R network is not visible to the outside world. But the principle corresponds to what can also be seen in the Wikipedia article mentioned above.

Regards,

/Peter

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kazuchib · ‎2022-02-13

I am making an application that changes voltage very quickly.

I replaced the microcomputer of another company with this microcomputer.

Even in previous applications, there was a temporary strange behavior when changing the voltage at high speed.

In the previous application, I thought about the correction method from the design information.

I would like to consider making corrections from the design information this time as well.

Peter BENSCH · ‎2022-02-13

OK, for timing problems with fast signals the internal setup is irrelevant, because the timing behavior of the whole DAC block and its possible error limits are listed in the datasheet, section 6.3.19.

Does it answer your question?

Regards

/Peter

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kazuchib · ‎2022-02-18

Sorry for the late reply.

Thank you for your answer.

I will proceed with the verification based on this material and the behavior of R-2R.

Best regards.