Step down converter LM2596 with voltage spike on output when powering up, destroys subsequent circuits
The spike problem may be due to a &quot;lag&quot; in feedback (resistor-dividing) circuit. It means there's a delay between feedback voltage and output voltage.
If you have added a capacitor in FB (Feedback) pin, remove it. If the problem still exists, add a small cap (in nF range) between FB (feedback) pin and output voltage.