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BQ25616: Schematic review requested, thermal runaway suspected

Jon Fick1
Prodigy 90 points
Part Number: BQ25616

Tool/software:

We're requesting a schematic review of our design.  There have been a few cases of thermal runaway and damage to the charger chip that necessitate replacement.  The chip seems to work fine, runs cool, but some random time that its plugged into USB, suddenly it's hot and damaged.  It's unknown if this is due to probing.

Attached is the schematic, four PCB layer images, and soldermask image.  The GND and VCC images are negative mask.  Thanks.

  • 0
    TI__Mastermind 40275 points

    Hello,

    My layout review is as follows:

    1. REGN node should not be loaded before the capacitor connection to ensure decoupling performance.

    2. SYS and BAT decoupling capacitors should be placed as close as possible to IC, they are not here.

    Please provide more information about the fail, it the USB line going to higher voltage?

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 90 points

    Mike,

    Thanks for looking at this.  ECs are noted.  And, from your review, I don't have any mis-wired or omitted connections.

    Regarding the three or four failures we are seeing...a colleague saw this twice, but he is a software developer with some capability in hardware.  Without a microscope he may have done damage during probing.  The line time the failure occurred in my own lab, I'm quite sure it wasn't due to probing issues.  The USB is a 5V-only supply; it can't go higher.  The next time this occurs, I will reopen this post and provide symptoms.

    Jon