Raspberry Pi HAT Design Overview

flux

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.
10 days
sejaltaypro16

sejaltaypro16

where you have conbcet on/off pin?
10 days

flux

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
10 days
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1y
4
L1
Inductance
33uH
VOUT
+5V
+5V
+5V
R2
Resistance
1kΩ
C3
Capacitance
470uF
R1
Resistance
3.0kΩ
C1
Capacitance
1.2nF
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LM2596 Buck converter 5V

LM2596 Buck converter 5V thumbnail
This project is a DC-DC Buck converter based on the LM2596 IC. It is designed to step down the input voltage from 12V to a regulated output of 5V #Buck #LM2596 #project

Properties

Properties describe core aspects of the project.

Pricing & Availability

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Qty 1

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$1.89–$3.76

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$2.96

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$3.70

Controls