LM27341: Part blows up when power is applied

Mike Sprauve

Part Number: LM27341

I am using a LM27341MY/NOPB in my onboard power system. It is being fed by 16.8V LiPo battery and outputting 3.0V to the board. I am using a simple SPDT slide switch to interrupt power. I also have a reverse protection diode in line. The board pulls a little more than 125 mA. The chip fails when I switch power to the system and the failure appears to start at pins 8,9, & 10. I have no destroyed several devices using the circuit but I am not sure what is causing the failure. All help is appreciated.

Thanks,

over 2 years ago

0 Nancy Zhang over 2 years ago

TI__Mastermind 46760 points

Hi Mike,

Could you capture some waveforms when you switch to interrupt power? Is it power up or power off? Make sure there is no voltage spike over absolute max rating 24V on pin8/9/10.

Thanks,

Nancy

0 Mike Sprauve over 2 years ago in reply to Nancy Zhang

Intellectual 380 points

Hi Nancy,

I will try to do what you suggested but I need replace the chip first since it blew on the last time I applied power. a couple of questions I have while the board is being repaired. 1) I have the EN pin tied to the power input, is that correct and then 2) Would you know if it is typical for a LiPo battery to have that kind of voltage spike when connected.

Thanks,

Mike

0 Shuai Fan over 2 years ago in reply to Mike Sprauve

TI__Genius 13381 points

Hi Mike!

Nancy will reply you next Monday!

Shuai

0 Nancy Zhang over 2 years ago in reply to Shuai Fan

TI__Mastermind 46760 points

Hi Mike,

1. EN tied to PVIN/AVIN is ok. Please see see below from datasheet section 7.4.1

2. I am not sure about the LiPo battery application. But if you used SPDT slide switch to power on/off, it is likely to have a voltage spike since SPDT slide switch is a mechanical switch. Please capture some waveforms to see if overstress the part.

Hope this helps,

Thanks,

Nancy

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LM27341: Part blows up when power is applied