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TPS51100: Operation at high temperature and thermal shutdown function

Guru 12235 points
Part Number: TPS51100

Hi,

My customer is currently using TPS51100 to evaluate at high temperatures (80 ° C  to 118 ° C).

 

1.  Please tell me the junction temperature of TPS51100 in "Recommended Operating Conditions".

  I could only find the Absolute Maximum Ratings in the datasheet.

2. The shutdown temperature TYP was listed in the data sheet.

 If you have any information about "Minimum", please let me know.

 

3. Is there a way to check if the thermal shutdown function is enabled?

 

Thanks,

Koki

  • Hi Koki,

    1. TPS51100 doesn't have recommended junction temperature spec, it only has recommended ambient temperature of 85C maximum. The device still can operate above 85C, but the parameters in the spec table may have wider tolerance. 

    2. I don't have min thermal shutdown temperature number, but based on the experience with other device, the variation can be +/-15C, so you can use 145C as min thermal shutdown temperature.  

    3. Thermal shutdown is always enabled, there is no option to disable this feature.

    Regards,

    Weidong

  • Hi, Weidong

     

    Thank you for your reply.

    My customers are evaluating at high temperatures.

    The evaluation results are summarized in an Excel table.

    Result and circuit diagram.xlsx

     

    Temperature measurement method

    A thermocouple is attached to the package, and the temperature is measured with a data logger.

    The thermocouple is attached with Kapton tape.

      

    Heating method

    The heating method is to place the device on a hot plate.

     

    Summary of evaluation result

    It was observed that the output voltage / current became unstable and the package temperature dropped a little when the load current was increased(around 2.3A) at high temperature.

      

    From the evaluation result, is the operation around 2.3A due to the thermal shutdown function?

      

    If you need more information, please let me know.

    Thanks,

     Koki

  • Hi Koki,

    I think it's due to thermal shutdown, so the output will transition between on/off when the temperature is high and trigger thermal shutdown, and cools down and turn on again. You can ask customer to measure the output voltage to verify this. 

    Regards,

    Weidong

  • Hi, Weidong

    You can ask customer to measure the output voltage to verify this. 

    I got VTT and VTTREF waveforms from my customer.

    When the analog probe was brought into contact with the pin to acquire the waveform, the voltage was sometimes stable even with a load current of 2.3A.

    Excel shows both unstable and stable waveforms.

    VTT and VTTREF waveforms.xlsx

    Judging from the waveforms, I would like your opinion on whether or not a thermal shutdown has occurred.

    Thanks,

    Koki

  • Hi Koki,

    Thanks for the waveforms, it looks it's thermal shut down. VTT turns off when temperature is too high, and then temperature goes down and VTT turns back on again. This process repeats if load current maintains at this level.

    Regards,

    Weidong