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TLV704: Is there a dv/dt maximum for this part?

Part Number: TLV704

Hi,

Posting this Q on behalf of my customer.

We have a part (TLV704345DBVR) that is used in production with no issue but we have used it in other smaller projects and it has a tendency to fail sometimes on power application. I suspect a latchup issue, but didn't see a spec in the datasheet. We are applying 19V and sometimes it just breaks/smokes (no output after). Could be some kind of line inductance that overvoltages it, but we haven't been able to repro that. Is there a dV/dT maximum for the input voltage?

Thanks!
Lauren

  • Hi Lauren,

    I have not come across any dV/dt limitations for this device.Given the information you've provided, there are a couple of failure mechanisms I can think of.

    It could certainly be an inductive spike which overvoltgaes the input, exceeding the abs max voltage and therefore damaging the device. This can happen to any LDO if the inductance on the input/output are too high and there is a high dI/dt event. 

    Another possibility is there being too much power dissipation across the LDO. This LDO does not have thermal shutdown protection, so if the junction temperature gets too hot for too long it could permanently damage the device. You mentioned it occurring during power up, do you have a large amount of output capacitance? This could cause a large inrush current event while the LDO tries to charge the output capacitor and before the current limit has time to kick in to limit the current. 

    Also what is the input source in the failing tests compared to the production application? If inrush current is the issue, then the output impedance of the supply to the LDO will dictate how much current the LDO can supply before the input supply droops. Lab supplies or applications with a large amounts of input capacitance will be more susceptible since they will be able to provide a large amount of current without the input voltage drooping much which results in a large amount of power dissipation. 

  • Hey Lauren,

    It's been a week and we haven't heard from you so I wanted to follow up and since it's possible you've resolved the issue. If not feel free to post again with some of the follow up information that I requested and we'll see what we can do to help.