• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 33 subscribers
  • Views 381 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MAX3238: MAX3238 Failure after a few weeks in field

Kenneth Hendrix
Prodigy 20 points
Part Number: MAX3238

We have a product that we have been selling for about a decade that uses a MAX3238C. Recently we had a production run and 3 devices failed in the field. One failed after a few days, another failed after a few weeks, and the third was installed back in December 2019.

Investigation into the issue discovered that the MAX3238C chip failed. Failure caused all the outputs to be less than one volt. The charge pump was oscillating but only also under a volt. Supply voltage was +5V. C1 = 0.22 uF and C2 – 4 were 1 uF. Force On and Force Off were both connected to +5V.

As this design has been in the field for almost a decade, and we have sold over 500, we don’t believe the issue is a design flaw.

We also did not uncover any external events that may have caused the failure. Each failure came from a different location. There was nothing different in the installation than any of installations done in the past. These are the first failures we have seen of the MAX3238C.

According to our records, the chips used in the past were also TI MAX3238C.

It occurred to us there may be a problem with the chips themselves. Possibly a CFSI issue. The markings on the 3 chips are all the same:

Top Line: (TI Logo) 52CYSEKC4, with the C4 underlined
Second Line: MAX3238C

Has anyone had failures with these chips?

Any assistance would be appreciated

  • 0
    TI__Guru 62920 points

    Hi Kenneth,

    Do you mind if I contact you via the email address on your myTI account?  The short answer is that we don't know of any issue related to this chip or this lot in particular, but I can share more info privately and I'd be interested to discuss your application's usage a little bit more in order to try to help with the debug efforts.

    Regards,
    Max

  • 0 in reply to Miguel Robertson
    Prodigy 20 points

    You can contact me through the email address on myTI account.  khendrix@agmelectronics.com

    I don't think the issue is due to how the MAX3238 is being used.  We have been using the board with the MAX3238C as far back as 2009, and created 300 units, without any issues until now.  The boards are being connected to another, older, device we manufacture that uses a MAX240 chip.  The devices are only a  couple of feet away from each other as they are mounted in the same panel and using the same power supply.  

    I think you may have already answered one of my questions.  The "52CYSEKC4" is a valid batch code.  The board using the chip is one we have assembled through a 3rd party, and while they have CFSI procedures in place we want to eliminate that possibility.

    One other possibility, is that they may have been damaged due to ESD.  It was my understanding these chips had some protection.  Is that protection on the RS232 I/O pins or for all pins.

    We're still evaluating the failure.  If you have any ideas please let us know.  Again, you can write to the khendrix@agmelectronics.com EMail address.

     

  • 0 in reply to Kenneth Hendrix
    TI__Guru 62920 points

    Hi Kenneth,

    I just sent you an email - please let me know if you didn't receive it.  To answer your other question, though, there is some level of ESD protection included on all pins but the 15 kV HBM rating mentioned in the datasheet applies specifically to the external interface pins (DOUT and RIN).

    Regards,
    Max