problem generating 5v using LM2596 Buck Converter IC

Projects General Guidance
1

Hello, I made one SMPS using LM2596-ADJ Buck converter IC to get 5v/2amps from it to power my external circuit.

I designed the Layout and tested the circuit on PCB three times till now but I am not getting stable output.

The last PCB which I designed provides 5v output for some time initially and later the voltage start fluctuating between 5-10v. I checked the values of feedback resistors properly and they are correct.

I have included the links for my schematic and Layout, I hope someone will help to resolve this issue.

https://drive.google.com/file/d/1C0IOHgW5fGKC2UehGiTHf3Yu1PCMOgkf/view

https://drive.google.com/file/d/1EamGO5s7WK7t8YmyqB9LEr42q_KHdYwO/view

The issue is only with SMPS circuit and not the rest of the circuits (LM1117, Under voltage lockout).

Thank You

2

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html .

Thanks.. Tom.. :slight_smile:

3

Hi,
Ops pics.

power supply.png
power supply.png1679×797 16.5 KB

power supply layout.png
power supply layout.png809×745 22.1 KB

Did you consult and read the design examples and suggestions in the data sheet for the converter, layout is very important.

Tom.. :slight_smile:

power supply.png
power supply.png1679×797 16.5 KB

power supply layout.png
power supply layout.png809×745 22.1 KB

4

I think that you are better off with a ground plane. The GND track looks to me too long for stable operation. But I'm not a buck converter expert... :wink:

5

Sorry for posting the question in inappropriate way.
Yes I read the datasheet and accordingly kept the components as close as possible.
I selected the value for capacitor and inductor from datasheet by keeping required output power in mind.