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TLV742P: Body diode rating

user6142633
Intellectual 440 points
Part Number: TLV742P

Hi,

What are the ratings for the body diode from OUT to IN on this device?

TLV742P was broken at evaluation. IN - OUT is shorted.
I think the possibility of body diode error.

Confirming the peripheral circuit, there was a time of OUT > IN in off-sequence.
And a few mA reverse current flowed during 5-10s.

Please advise the maximum ratings for the body diode of the pass mosfet.
I want to understand the cause of broken and countermeasure.

Hayakawa

  • 0
    TI__Genius 13175 points

    Hi Hayakawa,

    To limit the chances of damaging the LDO the reverse current should be limited to 5% of the nominally rated current which for TLV742 would be 10mA. 

    You can find more about reverse current and application topologies to protect LDOs from reverse current in this technical article on TI.com. 

  • 0 in reply to Kyle Van Renterghem
    Intellectual 440 points

    Hi,

    I understood the reverse current is limited of 5%.

    This percentage is DC value?

    Is there possibility that pulse reverse current as below destroy the body diode?

    Please advise the body diode rate If it changes with reverse current is pulse or DC. 

    Thanks regards,

    Hayakawa

  • 0 in reply to user6142633
    TI__Genius 13175 points

    Hi Hayakawa,

    Yes the 5% value is a DC current. 

    For a pulse we would expect the maximum value to be higher, however it will depend on the duration of the pulse however we do not have a good way to define what would be a safe value for this type of situation.

    The scope shot above is showing ~30mA for a few hundred microseconds and my gut reaction is that if that is the absolute worst case reverse current the device will ever see and it doesn't happen often then I would expect the device to survive this event. You will need to verify that the device still meets the requirements of the application but based on the large number of cases I've seen I wouldn't expect this one event to destroy the LDO. That being said I would recommend implementing one of the protection schemes mentioned in the article I attached previously to ensure devices aren't damaged in the future. 

  • 0 in reply to Kyle Van Renterghem
    Intellectual 440 points

    Hi,

    Thank you for your advise.
    Of course, I will implement protection schemes.

    Please tell me for reference.
    For example, if pulse width is 1ms, how much current can be survived in terms of allowable loss for body diode ?

    Hayakawa

  • 0 in reply to user6142633
    TI__Genius 13175 points

    Hi Hayakawa,

    Based on what I've seen on many different LDOs, I'd expect it to likely survive ~50mA for 1ms assuming it doesn't happen often.