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ADS1232: ADS 1232 startup serious problem

Claudio Brunelli
Prodigy 20 points
Part Number: ADS1232

Good morning to everyone.

We use the ADS1232 AD since 2007 and it’s very good for our balances application. Suddenly, in our production, we have a serious problem to the power on reset.

We didn’t change anything both in the hardware and in the firmware. But now, at the beginning of the power on the converter sometimes and random seem to be locked. And nothing can be done to unlock it. Only another, power on reset directly from the power supply unlock it. This strange condition it isn’t systematic. On the same board 6-7 times appear but not in all production. But the total percentage is a bit worrying.

I checked components, values, board and all seem to be right. Even the pin N° 22 PWD has a RC filter about 1 ms.

I never had any problems like this and I hope someone can help me. If it was necessary I can give more details.

 

Thanks a lot.

Claudio

  • 0
    TI__Guru** 113765 points

    Hi Claudio,

    Welcome to the forum! Do you have the ability to control the PDWN pin with a micro GPIO?  We have discovered that the RC on the PDWN may not be the best solution when powering up the ADS1232 due to process variation in fabrication.  In some cases a PDWN pulse is required to properly reset the device into the correct operating mode.  After the supplies have settled wait 100ms, then pulse the PDWN pin.  This should sufficiently reset the device.  We hope to get this recommendation into the datasheet in the near future.

    Another thing to also check with your hardware is to make sure you do not have large overshoots or undershoots when powering the ADS1232.  This can be caused by inductive traces or changes in capacitive loading.  You should have a good ground plane on your PCB and not just connecting traces to ground.

    Also, have there been any BOM changes to components?

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 20 points

    Hi Bob.

    I thank  you for your reply.  In my feeling, not finding a solution I thought of something like that. I have a GPIO available and now I try immediately.Because we use a lot of your converters.

    It would be advisable to update the data sheet.

    Thanks Bob for your assistance !

    Claudio