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TPS2553: Question regarding OTP

Patty Chuang
Intellectual 1155 points
Part Number: TPS2553

Hi Team,

my customer has question about TPS2553 OTP. they measured the Tc and calculate the Tj that is high than 135 degree. But it did not trigger OTP. Please help to explain it.

Below is the info for the testing.

 

OCP protection parameters

Vin= 3.3V

Vout= 0.05V

Iout= 0.4A

Efuse = (3.3-0.05)*0.4=1.3W

measured Tc= 60ºC

calculated TJ= 60+ 122.2*1.3= 218ºC

 

 

 After testing, OCP tried to trigger OTP but it failed as below:

Please kindly advise, thanks!

Patty

  • 0
    TI__Mastermind 18031 points

    HI Patty,

    You try short to GND and see what happened,

    Increasing the current gradually and check whether can thermal cycle.

    If not, try change another IC.

    For TI's policy, I will first click resolved button.

    If you have any other concern, contact me any time.

    If you think resolved, please help click 'Issue is solved button'.

    Thanks.

  • 0
    TI__Intellectual 1155 points

    Hi Ziv,

    customer feedback that no matter what current they loaded even short output, load current will be clamped at OCP after trigger fault.

    So , I think if we increase OCP, thermal dissipation will also be increased. Then that will trip OTP as waveform shown in datasheet.

    But We concerned about calculation format.  If it is correct, why NO OTP?

    Please help to comment, thanks!

    Patty

  • 0 in reply to Patty Chuang
    TI__Mastermind 18031 points

    Hi Patty,

    For junction temp calculation, you should use ψJT instead of RJC. RJC is a parameter with a heat dissipation and heat flows by one direction.

    ψJT is more practical to real case which heat flow by all directions.

    If short to GND, it's sure to thermal cycle. The results from customer side is not correct.

    Have you ever tested on EVM board? Or change one new IC?

    Or send me the schematic for a check.

    For TI's policy, I will first click resolved button.

    If you have any other concern, contact me any time.

    If you think resolved, please help click 'Issue is solved button'.

    Thanks.