TPS54386 gets super hot!

HPB

Other Parts Discussed in Thread: TPS54386

Hi, I built three power supplies with the TPS54386. One is a 12V-5V and the other two are 5V-3.3V. One of these three does not seem to work. When I connect the input power, the chip gets really hot and there is nothing on the output. The other two (12V-5V and the other 5V-3.3V) are working fine. I checked all the component connections and their values too. I also checked for accidental shorts and other such incidents. Everything seems to be great with the board. Also the other two were tested with the same supply and under the same load conditions. What am I missing here?

over 10 years ago

0 JohnTucker over 10 years ago

TI__Guru**** 191445 points

Can you post your schematic and layout?

0 HPB over 10 years ago in reply to JohnTucker

Expert 1350 points

Sure. I've attached it here. The other two are working great without any heating.

export.zip

0 HPB over 10 years ago in reply to HPB

Expert 1350 points

Any solution to my problem? I did replace the chip with another one and this it literally went up in flames.

0 JohnTucker over 10 years ago in reply to HPB

TI__Guru**** 191445 points

I do not see anything obvious except your unregulated ac source. I would try powering the circuit directly from a dc lab supply to see if the input rectifier is the problem. It may have too much ripple component or possibly over voltage spikes.

0 HPB over 10 years ago in reply to JohnTucker

Expert 1350 points

Thanks John. Though the provisions for using an AC source are there, I had not used them in my board. I had powered the whole thing through a DC wall cube. The input supply is a little more than 16V DC. I'm going to check the whole board now for connectivity and also other components that are there.

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TPS54386 gets super hot!