I'm currently using a 42V lithium battery (42v when fully charged) and converting it to 3.3V DC to power an ESP32 using an LM2596HVS buck converter.
However, I'm encountering numerous false interrupts from adxl245 sensor. Interestingly, when I replace the battery with a 12V adapter connected to the LM2596HVS (convert 12V to 3.3V), everything operates normally without any false interrupts.
Any insights or suggestions on why this might be happening would be greatly appreciated!
A scope were very helpful with such problems.
Perhaps the converter should have a bigger load capacitor or more load current at a high I/O voltage ratio.
i have this cheap scope https://vi.aliexpress.com/item/1005006514685089.html idk if it can help
Use it to inspect the 3.3V and the interrupt line for spikes.
With a stepdown ratio of less than 0.1 (3.3/42) the performance of any buck converter will start to deteriorate.
Your best solution is to go in two steps, first 42 to 12V then 12 to 3.3V. The output capacitor must have a low ESR
Hi, @arpa123
Can you please post some images of your converter?
So we can see your component layout, working at high frequency switching can have its problems.
Did you buy a module or build one yourself.
Note the tight grounding requirements
Because you are using 42V input, the SMPS duty cycle will be quite small compared to when using 12V input.
This would possibly produce noise/glitches on the output supply.
You may need to place a shield over the supply and keep your power wires short.
If you are using a module, where did you purchase it, I would question its ability to perform to specification.
Tom... 
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