TPS61196: it fails

Paolo Colombara

Part Number: TPS61196

Dear sirs,

I have designed a board which implements one TPS61196 device. However, the design has proven to be unreliable, because to date we have received back 15 faulty boards out of around 40 which have been sold so far. The problem appears to be always the same: the pin which connects to the MOSFET gate does not output any signal anymore. The Alarm LED lights up, so apparently some part of the chip still works, but the MOSFET remains off. After replacing the TPS61196, the board resumes correct operation, so no other components have been damaged.

I am attaching the schematic; the board contains 180 LEDs, divided into 6 strings of 30 LEDs each. Current = 85mA/string. We should be well within limits.

The marknig on all broken chips reads:

TPS61196Q

O2T

AY17

Can you give me a hint for the apparently inexplicable destruction of the chips?

Thanks, best regards

Paolo

over 3 years ago

0 Patrick Yao over 3 years ago

TI__Mastermind 35560 points

Hi Paolo,

Where did you buy these devices? And have you moved these "fault" devices to other boards and re-test again?

Patrick

0 Paolo Colombara over 3 years ago in reply to Patrick Yao

Intellectual 260 points

Hi Patrick, thanks for your reply.

We bought them from digikey, so I hope they are legitimate. I did not try to move the faulty component to another bosrd, I did the opposite: I replaced the faulty component with a new one and the board resumed its proper operation...

Do you suspect any production issue?

0 Patrick Yao over 3 years ago in reply to Paolo Colombara

TI__Mastermind 35560 points

Hi Paolo,

It's recommended for you to request a failure analysis, please contact your local FAE or sales in TI. They will help you with it.

Patrick

0 Paolo Colombara over 3 years ago in reply to Patrick Yao

Intellectual 260 points

Hi Patrick,

I am trying to organize the failure analysis but it is not so quick and easy... just to have an idea, do we need to collect all failed components and send them to you? and also unused ones? Thanks

0 Dave Yaeger over 3 years ago in reply to Paolo Colombara

TI__Intellectual 2925 points

Hi Paolo,

Our experts for this issue are currently celebrating the Chinese Golden Week holiday, they will respond to you next week.

Regards,

Dave

0 Patrick Yao over 3 years ago in reply to Paolo Colombara

TI__Mastermind 35560 points

Hi Paolo,

Have you contacted TI local FAE or sales team?

Patrick

0 Paolo Colombara over 3 years ago in reply to Patrick Yao

Intellectual 260 points

Hi Patrick,

yes, they have diverted me to the distributor, but still I have been unable to obtain proper information.

Now my question is: I have collected 12 damaged components; are they what you need to conduct failure analysis or do you also need extra "new" components from the batch under investigation?

Thanks,

Paolo.

0 Patrick Yao over 3 years ago in reply to Paolo Colombara

TI__Mastermind 35560 points

Hi Paolo,

I don't have resource to do FA at my site, you should contact FAE to help you to request.

Did they help you to CQE yet?

Patrick

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TPS61196: it fails