The unstable of sine wave generating signal by DAC

Forum|Forum|4 years ago
June 1, 2021
2 replies
2085 views

Hello, I have the problem of sine wave generation by DAC. Time to time when I generate the sine wave signal from MCU (STM32F302R8T6), the signal is unstable. I try to debug, and found that the issue might results from the hardware which is MCU. I would like to ask what is the solution to solve this issue.

I have upload the schematic, the code and the video.

This is the video link : https://drive.google.com/file/d/14H5SwWmWiqGRgMHV2Tm5EA9vfEXYJYwO/view?usp=sharing

Thank you

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G

Gudgel.boB

Graduate

It looks kind of like the DAC output might be intermittently hitting another trace that has 3.3V on it.

I would look at the traces adjacent to the DAC output just in case that is happening. Maybe even the micro pins on either side of the DAC pin.

Also, what happens if you try tapping the PCB in the DAC trace area ? Does it make the problem better or worse ?

Have you tried another PCB and micro ? I am guessing that what you show in your video doesn't happen on a second unit.

boB

S

SPhon.1Author

Visitor II

Hi boB, First of all thank you for your help. I check the rule of PCB design. So, the clearance between each trace is 6 mil (0.15 mm).

Do you think that it is too close for the PCB trace? By the way, I assembled another board (same PCB design) and tested it, but the problem still happened to another as well. Actually, it just worked in the beginning. Then, the issue occurs. I have no idea to solve it. If you have any idea to solve this issue, please let me know.

Thank you