Raspberry Pi HAT Design Overview
0:14
For the LM2596 ON/OFF pin, connect it so the regulator is enabled by default.
- The ON/OFF pin is a control pin on this regulator family, not a power or output pin, so it should be treated as part of the control network rather than tied into the switch node or output path
- In your HAT design, if you do not need remote shutdown, the practical connection is to tie ON/OFF to ground / Power_GND so the buck converter stays on.
- Do not leave it floating.
- If you want a manual enable/disable later, connect ON/OFF to a switch or transistor that can pull that pin high/low, but keep it referenced to the power-side ground, not the Pi isolated ground plane.
Given your isolation requirement:
- Connect LM2596 ON/OFF to Power_GND
- Keep it on the 24 V / buck converter side
- Do not route it across the opto-isolation barrier
If you want, I can also show you the full fixed 5 V LM2596 pin-by-pin connection list for your design.
13 days
0:12
I don’t see any uploaded-file evidence showing that the LM2596 ON/OFF pin is already connected somewhere in your design. The file search results returned only general guidance files, not a schematic snippet or net listing for that pin, so I can’t point to an existing connection from the uploaded material
So the direct answer is:
- If you’re asking “where should I connect it?” → connect ON/OFF to the power-side ground so the regulator stays enabled.
- If you’re asking “where did you connect it in the design?” → I did not verify an actual placed connection from the uploaded files; there isn’t enough file evidence to claim it is already wired anywhere
For your board, that means:
- LM2596 ON/OFF -> Power_GND
- Keep it on the buck / 24 V side
- Do not connect it to the isolated Pi ground plane
- Do not leave it floating
If you want, I can next help you identify the exact LM2596 pin number for ON/OFF from the datasheet and give you the full pin-by-pin connection map.
Pin map please
Check datasheet pin
Review ground domains
13 days
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