TPS62086: , Explosion of the tantalum capacitor connected to the TPS62086 output

maceti

Part Number: TPS62086

Hello,

I have been designing with LTE/4G modules for many years and I use TPS62086 for power.(used in 20k+ pieces board)
LTE module manufacturers recommend 2 parallel 470uF tantalum capacitors in the module power circuit(3.3V) and I use these 2 x parallel 470uF capacitors without any problems by connecting the output of TPS62086.
Unlike our previous designs, this time we connected the PG pin to the output with a 1 Megaohm resistor.
And in the tests of 1k of our 4k boards, tantalum capacitors exploded in 2 boards. After energizing the board, it exploded in 2-3 seconds.

My schematic is here:

Could this explosion be caused by the PG pin being connected?
Or what do you think might be the reason for this explosion, can you suggest something else?
Thank you

over 3 years ago

0 Febin over 3 years ago

TI__Mastermind 27280 points

Hi,

The attached schematic and layout cannot be opened.

Also, snippets will not help. Please share the full schematic and layout.

Regards,

Febin

0 maceti over 3 years ago in reply to Febin

Prodigy 230 points

Hi Febin,

Thanks for your answer.

Sorry for the images not opening.

It will now open.

Exploding capacitor:
drive.google.com/.../view

Schematic:

drive.google.com/.../view

In addition, when 2 pieces of 470uF tantalum were connected in this way at the output of the TPS62086, could it have exploded due to the inrush current?

0 Sneha over 3 years ago in reply to maceti

TI__Expert 8756 points

Hi Maceti,

Please allow me to take care of your request as Febin is out of office this week.

I will review your request and give you a feedback by later today.

Thanks!

Best regards

Sneha

0 maceti over 3 years ago in reply to Sneha

Prodigy 230 points

Hi Sneha,
OK, thanks. Waiting for your reply.

0 Sneha over 3 years ago in reply to maceti

TI__Expert 8756 points

Hi Maceti,

I checked the schematic and I do not think connecting PG to the output via 1M resistor would cause any issue as it is as per datasheet recommendations.

One reason I could think for a tantalum capacitor explosion is that if a reverse voltage is applied to it. Can you confirm if the capacitors were properly assembled with the correct polarity?

I also came across this article in the internet https://www.edn.com/what-a-cap-astrophe/ which says that it might also be caused due to manufacturing defects as well.

I addition, Can you share the reason of using large value tantalum capacitors near to the IC? Just as a side note, I would like to mention that having such high capacitors outside of the LC matrix recommendation in the datasheet might lead to unstability issues

Thanks!

Best regards

Sneha

Power management

Power management forum

TPS62086: , Explosion of the tantalum capacitor connected to the TPS62086 output