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TPS23881: Firmware reset when eFuse is blown

Tristan Robinson
Prodigy 280 points
Part Number: TPS23881

Hi, can you please assist with this customer question regarding TPS23881:

We are using the part in a 4-Port 4-Pair configuration. Our design slightly differs from the recommended application (figure 10-2) in the datasheet with respect to the fuses. Instead of having individual slow blow fuses in the return path of each coil, we have a single one at the supply (+54V) for both coils, i.e. one fuse for each RJ45. The fuse we are using is the TPS26600RHFR eFuse.

The Issue... For some reason, whenever a fuse is triggered the TPS23881 is reset. I have observed both the RESET pins and +3V3 rail during this, and can confirm no glitches appear. Upon reset the TPS23881 also reverts from its loaded firmware (v14) for the original (v0) but I think that's to be expected.

Our circuit:

Many thanks,

Tristan

  • 0
    TI__Genius 15275 points

    Hi Tristan,

    The device being reset is not expected behavior. Can you capture waveforms for Vpwr, RESET, and Vdd to ensure there is no dip. Can you also read register 0x00 to ensure there are no faults being thrown. 

    SRAM would only be lost if the device is being reset. What are the conditions for the fuse being blown? 

    Regards,

    Brandon