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TPS25923: TPS259231DRCR-

Vivek V
Prodigy 20 points
Part Number: TPS25923

Tool/software:

Hi Team,

In one of our projects, we are using the following IC for protection purposes at the input side of the CCA:

TPS259231DRCR - IC Electronic Fuse 8% 10VSON - Texas Instruments

However, during some field runs, we experienced 5 failures out of 50 units.

From one of our field reports, we learned that the connections were made in reverse. The rest of the RCA work is still in progress. Kindly find the schematic image below for reference.

Please share your insights. Additionally, let me know whether this part simply fails if connected in reverse polarity

  • 0
    TI__Guru** 104466 points

    Hi Vivek,

    Is VIN going beyond abs max of eFuse due to L6.?

    Can you perform hot-plug and output short-circuit tests and check.

    BR,

    Rakesh

  • 0
    TI__Mastermind 22900 points

    Hi Vivek,

    Yes, if you plug the device in reverse polarity, the Vin will see input <-0.3V which will violate the abs min of the device. Kindly check on the other questions mentioned by Rakesh also, they can also result in device failure.

    Best Regards,
    Arush

  • 0 in reply to Rakesh
    Prodigy 20 points

    Waveform during hot plug.pdf

    Hi Rakesh,

    Thanks for the reply.

    The input is 5V.

    As you mentioned, I performed both the hot-plug and output short circuit tests with and without L6 (short), and I captured the waveforms as well.

    However, I did not notice any difference in the waveforms; both are similar. There is a spike during the "on" time that goes up to 50V, but it lasts only for 20ns.

    Please check the attached images.

  • 0 in reply to Arush Gupta
    Prodigy 20 points

    Hi Arush,

    Thanks for the response.

    In TPS25923 don’t we have built-in protection mechanisms (like internal diodes) that prevent current flow when the input is reversed? Also, in the datasheet, it mentions reverse current protection. Is that only for load reverse current?

    Also as per the feedback from field they are mentioning they have not connected in reverse what can be other reasons for failures.  please refer the comment I provided to Mr. Rakesh as well.

  • 0 in reply to Vivek V
    TI__Mastermind 22900 points

    Hi Vivek,

    Vivek V said:
    In TPS25923 don’t we have built-in protection mechanisms (like internal diodes) that prevent current flow when the input is reversed? Also, in the datasheet, it mentions reverse current protection. Is that only for load reverse current?

    I think you are getting confused between reverse current blocking (which is supported in this device using external blocking FET. this blocks current from OUT to IN) and reverse polarity protection (flipping the inputs supply terminals). I see that reverse current blocking is implemented in the schematic. 

    Vivek V said:
    There is a spike during the "on" time that goes up to 50V, but it lasts only for 20ns.

    It looks like the Vin is going very high (abs max is 20V). Are you seeing same 50V spike without L6 also? 

    Do you or your team have access to the failed devices. Can you ask them to check pin impedances of the damages devices (Use DMM, capture in diode mode from GND to all pins). Can you also ask if there is any physical damage (some images).

    Best Regards,
    Arush

  • 0 in reply to Arush Gupta
    Prodigy 20 points

    Dear Arush

    I received the failure part from field below are the details 

    PINS Failure board Working board
    Diode mode Resistance mode Diode mode Resistance mode
    1 0.663V 11M 0.654V 10.9M
    2 0.563V 10K 0.561V 10K
    3,4,5 0.571V 25K 0.567V 25K
    6,7,8 0.360V 1K 0.357V 1K
    9 0.629V 1.2M 0.622V 1.23M
    10 0.691V 97K 0.689V 97K

    Regarding Spike with and by shorting L6 pins, we observed same spike attached the images for reference

  • 0 in reply to Vivek V
    TI__Mastermind 22900 points

    Hi Vivek,

    I don't see any issue in the esd structures for the failed device. Are you seeing IN-OUT short fails? I feel this 50V transient is causing the damage. We should be able to clamp this using TVS diode at the input. We use SMC series TVS in our EVM. 

    Best Regards,
    Arush